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Computational approaches to the study of genomic roles of repeated DNA sequences Van de Lagemaat, Louie Nathan 2006

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COMPUTATIONAL APPROACHES TO THE STUDY OF GENOMIC ROLES OF REPEATED D N A SEQUENCES by LOUIE N A T H A N V A N DE L A G E M A A T B.A.Sc, The University of British Columbia, 1996 A THESIS SUBMITTED LN PARTIAL F U L F I L L M E N T OF THE REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY in THE F A C U L T Y OF G R A D U A T E STUDIES (Genetics Graduate Program) THE UNIVERSITY OF BRITISH C O L U M B I A April 2006 © Louie Nathan van de Lagemaat, 2006 Abstract Repeated sequences make up nearly half of the bulk of mammalian genomes and vary widely in structure and function. This thesis describes computational approaches for assessment of interaction of repeats and their host genomes. Following public release of the human genome sequence, initial investigations focused on overall distributions of retroelements with respect to sequence composition and genie position. Exclusion of various retroelements from regions both within and surrounding protein-coding genes suggested selection against the presence of these elements. Directional biases of accepted retroelements in these regions further supported this notion. Directional biases are understood to reflect differential mutagenicity by sequences in one direction vs. the other. To examine the relationship between protein-coding genes and mobile elements further, mappings of genomic transposable elements in the human and mouse genomes were examined in relationship to positions of all exons of protein-coding gene mRNAs. I found that approximately one quarter of mRNAs of protein-coding genes harbor sequence contributed by transposable elements. The fact that transposable element sequence is most often found in untranslated regions (UTRs) suggests a highly significant role for these sequences in modulation of translation efficiency in addition to roles in transcription. Further investigations used directional biases of retroelements in transcribed regions in humans and mice to show that transposable elements transcribed by RNA polymerase II (pol II) exert varying effects upon insertion, depending on the sequence of the element. Finally, a bioinformatic study done on global insertion patterns of retroelements since human-chimpanzee divergence revealed that some transposable elements polymorphic for presence or absence in primate genomes actually represented ii deletions rather than de novo insertions. These deletions were flanked by short tracts of identical sequence, suggesting deletion by recombinational mechanisms. The relative rarity of these events lends support to the assumed stability of transposable element insertions while illustrating the recombinational activity of even low-copy, nonadjacent, short repeated sequences, such as those found flanking transposable element insertions. In summary, these bioinformatic studies lend insight into the biological roles and genomic effects of mammalian genomic repeats, especially transposable elements. iii Table of Contents Abstract i i Table of Contents iv List of Tables vi List of Figures vii List of Abbreviations viii Acknowledgements ix Chapter 1: Introduction 1 1.1 Thesis overview 2 1.2 Sequence motion: what, how, why, and where to? 3 1.2.1 Discovery of repetitive D N A 3 1.2.2 Mobile elements and their modes of transposition 3 1.2.3 Mutagenic roles of transposable elements 12 1.2.4 Relationships between initial and long-term distributions of TEs 18 1.3 Neutral or beneficial roles for TEs in the transcriptome 21 1.3.1 Regulatory motifs donated by TEs 21 1.3.2 Protein domains donated by TEs 24 1.4 Stability of repetitive sequence 25 1.4.1 Assumptions of stability and use of retrotransposed sequence as population markers 25 1.4.2 A role for D N A double-strand break (DSB) repair in creating de novo insertions, deletions, and tandem duplications 26 1.5 Repeat finding methods 28 1.6 Thesis objectives and chapter summaries 29 Chapter 2: Retroelement distributions in the human genome 33 2.1 Introduction 34 2.2 Methods 36 2.2.1 Description of retroelements 36 2.2.2 Data sources 37 2.2.3 Density analysis 37 2.3 Results and Discussion 39 2.3.1 Distributions of retroelements in different GC domains 39 2.3.2 Arrangements of retroelements with respect to genes 45 2.3.3 Shifting retroelement distributions with age 50 2.3.4 Length differences do not account for the shifting patterns 56 2.3.5 Delay of Alu density changes on the Y chromosome 58 2.3.6 Potential explanations for Alu distribution patterns 59 2.4 Concluding remarks 62 Chapter 3: Analysis of transposable elements in the human and mouse transcriptomes.. 65 3.1 Introduction 66 3.2 Methods 66 3.2.1 Prevalence of TEs in human and mouse gene transcripts 66 3.2.2 Variation of TE prevalence with gene class or function 67 3.3 Results and Discussion 68 3.3.1 Prevalence of TEs in human and mouse gene transcripts 68 3.3.2 TEs serve as alternative promoters of many genes 69 iv 3.3.3 TE prevalence varies with gene class or function 75 3.3.4 TEs are more prevalent in mRNAs of rapidly evolving and mammalian-specific genes 79 3.4 Conclusions 81 Chapter 4: Analysis of genie distributions of endogenous retroviral long terminal repeat families in humans 82 4.1 Introduction 83 4.2 Methods 84 4.2.1 Directional bias of insertions in transcribed regions in mice 84 4.2.2 Directional bias of retroelements in the human genome 84 4.3 Results and Discussion 86 4.3.1 Opposite orientation bias of fixed versus mutation-causing retroviral insertions 86 4.3.2 Variation in density of genie insertions of different H E R V families 87 4.3.3 Density profiles of ERVs across transcriptional units 90 4.3.4 Distinct pattern of HERV9 elements with respect to genes 93 4.3.5 S V A SINE elements display distribution patterns similar to LTRs 94 4.4 Concluding remarks 96 Chapter 5: Analysis of repeats and genomic stability 98 5.1 Introduction 99 5.2 Methods 101 5.2.1 Direct assessment of retroelement deletion rate 101 5.2.2 Detection of deletions internal to Alu elements 102 5.2.3 Assessment of deletion frequency due to illegitimate recombination.... 102 5.2.4 Genomic PCR and sequencing 103 5.3 Results and Discussion 104 5.3.1 Direct assessment of retroelement deletion frequency 104 5.3.2 Analysis of random genomic deletion by illegitimate recombination.... 110 5.3.3 Direct confirmation of Alu element deletions 113 5.4 Concluding remarks 117 Chapter 6: Summary and conclusions 119 6.1 Summary 120 6.2 Initial and long-term genomic localization of mobile elements are related in complex ways 120 6.3 Some TEs interact strongly with genes, leading to population biases in regions surrounding genes 121 6.4 Many gene UTRs are associated with TE-derived sequence 122 6.5 Short repeated sequences are involved in genomic deletions 123 6.6 Conclusions 125 References 127 Appendix A 140 List of Tables Table 1.1 Human TE types, copy numbers, genomic coverage, and mutation occurrence 4 Table 2.1 Significance (p-values) of retroelement locations with respect to genes 49 Table 2.2 Significance (p-values) of distributional differences between divergence cohorts 55 Table 2.3 Significance (p-values) of distributional difference between Alus on the Y chromosome versus the whole genome 58 Table 3.1 RefSeq transcripts beginning within a previously unrecognized TE 71 Table 3.2 Domains associated with TE enrichment or exclusion in mRNAs 78 Table 4.1 Annotated copy numbers and evolutionary ages of various E R V familes 88 Table 5.1 AluS indels assayed in primates by PCR and B L A S T 114 vi List of Figures Figure 1.1 Full length endogenous retrovirus-like elements 7 Figure 1.2 L I structure 8 Figure 1.3 Typical Alu element of -300 bp 9 Figure 1.4 Structure of a typical S V A element, found at human chromosome 13ql4.11.10 Figure 1.5 Target-primed reverse transcription (TPRT) 11 Figure 1.6 Transcription control elements of the M L V LTR 16 Figure 1.7 Orientation of TEs that contain human gene transcriptional start sites 23 Figure 2.1 Density of retroelements in different GC fractions in the human genome, calculated over 20-kb windows across the genome sequence 41 Figure 2.2 Density of retroelements as a function of average GC content of each human chromosome 44 Figure 2.3 Ratios of observed to predicted retroelement densities with respect to genes in the human genome 46 Figure 2.4 Retroelement densities of different divergence classes in various GC fractions of the human genome 51 Figure 2.5 Length distribution of retroelements with respect to surrounding GC content57 Figure 2.6 Density of Alu divergence cohorts in different GC fractions on chromosome Y compared to the whole genome 59 Figure 3.1 TEs in genes by species and orientation 69 Figure 3.2 Examples of genes with apparent TE-derived promoters 73 Figure 3.3 Prevalence of TEs in mRNAs of various gene classes 76 Figure 4.1 Directional bias of retroelements in mouse transcribed regions 87 Figure 4.2 Orientation bias of various full length ERV sequences in genes 89 Figure 4.3 Patterns of annotated ERV presence in equal-sized bins across transcriptional units 92 Figure 4.4 Insertion pattern of S V A and AluY retroelements across transcriptional units. 95 Figure 5.1 Deletions due to D N A double strand break repair 108 Figure 5.2 Prevalence of direct repeats at deletion boundaries 112 Figure 5.3 PCR and sequence evidence for precise Alu element deletion 114 Figure 5.4 Sequence evidence for precise Alu element deletion 116 vii List of Abbreviations A L V Avian Leukosis Virus B L A S T Basic Local Alignment Search Tool B L A T Blast-like Alignment Tool DSB double strand break ERV endogenous retrovirus(like) ETn Early Transposon GO Gene Ontology HERV human E R V HIV Human Immunodeficiency Virus HR homologous recombination IAP intracisternal A particle indel insertion/deletion IPR InterPro IR inverted repeat K O G euKaryotic clusters of Orthologous Groups LINE long interspersed nuclear element LTR long terminal repeat MaLR Mammalian apparent LTR Retrotransposon MER4 MEdium-Reiterated repeat 4 M L T Mammalian LTR Transposon M L V (Moloney) Murine Leukemia Virus M R N MRE11/RAD50/NBS1 (protein complex) NCBI National Center for Biotechnology Information NHEJ nonhomologous end joining ORE open reading frame PCR polymerase chain reaction pol II R N A polymerase II RPA replication protein A SINE short interspersed nuclear element SIV Simian Immumodeficiency Virus SSA single strand anealing ssDNA single stranded D N A TE transposable element TPRT target-primed reverse transcription TSD target site duplication UCSC University of California Santa Cruz UTR untranslated region viii Acknowledgements Reflecting over the work described here, I would like to thank many people for their input and give them credit for the role they have played in my work. First of all, many thanks go to my supervisor, Dr. Dixie Mager. Besides being a smart and insightful person, she has been a fun and interactive supervisor, and conversation with her has always been profitable. I really appreciated the measure of freedom she gave me to pursue particular aspects of the questions at hand, and she was always ready to discuss new data, especially when there were graphs to look at. Furthermore, it's been fun getting to know past and present members of the Mager Lab and the broader BC Cancer Research Centre community, and I thank them all for their friendship and input. Further credit is due to many people who have been involved with my projects in various supportive roles. First in this regard have been my thesis committee members, who have contributed in various ways to my success. Drs. Ann Rose and Steven Jones have been a source of good questions about my data, and in more than one instance, have led to positive development of my projects. Dr. Holger Hoos's contributions in the realm of algorithm development have led to some of the software developed in the course of this work. In addition to my committee, I thank the National Science and Engineering Research Council of Canada and the Canadian Institutes of Health Research for generous funding during the course of my work. Very importantly, I feel very grateful to Patrik Medstrand for his involvement all my PhD long. I suppose our relationship goes beyond a supervisor-student relationship into the realm of personal friendship. I have learned a great deal from Patrik, and the exchange visits to his lab in Sweden have been productive, and more than that, lots of ix fun. Thanks also goes to Patrik's wife Lilly, and my hosts in Lund, the Bruce family. Last and definitely not least, I thank my parents, Wulf and Henrietta, for all their love and interest in my work. I have always enjoyed the discussions we have had. x Chapter 1: Introduction 1.1 Thesis overview The goal of this thesis project was to use global computational genomic analyses of repeated sequences in mammalian genomes to understand interactions o f these elements with their host genome. Repetitive sequences, including transposable elements and tandem and segmental duplications, make up nearly half of mammalian genomes. Repeated sequences influence the host genome in several main ways, from the obvious role in genome expansion to generation of distributed similar sequences susceptible to ectopic recombination, to provision of transcriptional and regulatory signals. A s early as Barbara McCl in tock ' s experiments in maize in the 1950s, there was some appreciation of the cytogenetic and concomitant regulatory consequences of D N A that could move about in a genome. However, only more recently have molecular studies begun to unravel some of the mechanisms involved in amplification of repetitive sequence and the mechanisms mediating the regulatory roles of repetitive elements fixed in mammalian genomes. These advances in understanding, coupled with the availability of the sequenced genomes of humans and various model organisms, have enabled further genome-wide studies of repeated sequences and their role in organismal biology. The research reported in this thesis attempted to clarify the dual roles of transposable elements and other repetitive sequences and their potentials for both benefit and harm. Primarily, bioinformatic and mapping techniques were used to elucidate these roles with occasional additional validation using wet laboratory approaches. These approaches make it possible to address questions regarding global genomic processes and how repetitive D N A has shaped genome architecture. 2 1.2 Sequence motion: what, how, why, and where to? 1.2.1 Discovery of repetitive DNA Mammalian genomes may best be described as a patchwork of many types of sequences, including genes, control regions, and, not mutually exclusively, repeated sequences. The first hints of the pervasive presence of repeated sequence in genomes date back to the early 1950s, when it was observed that the D N A content of cells, which was presumed to contain the genes, was poorly correlated with the overall level of complexity of the organism (the so-called C-value paradox), reviewed in Gregory (2001). One early explanation proposed that the extra D N A was 'junk', or non-coding pseudogenes, while later theories suggested it to be self-replicating 'selfish D N A ' (Doolittle and Sapienza 1980; Orgel and Crick 1980). The discovery of mobile or transposable elements by Barbara McClin tock a half century ago (McClintock 1950; McClin tock 1956) and subsequent discovery of retrotransposable elements has better explained the nature of this 'selfishness'. 1.2.2 Mobile elements and their modes of transposition Thorough study of the human genome has shown that recognizable repeats make up nearly half of its bulk (International Human Genome Sequencing Consortium 2001). Lesser coverage by repeats in other mammalian genomes, for example in rodents, has been attributed to the incompleteness of the library of known rodent repeats as well as faster substitution rates in the rodent lineage, and therefore the estimates of approximately 40% repetitiveness of rodent genomes are considered to be lower bounds (Mouse Genome Sequencing Consortium 2002; Rat Genome Sequencing Project Consortium 2004). 3 Several broad categories of repetitive sequence exist. One of the most basic distinctions one can make is related to copy number. Low copy number repeats, including tandem and segmental duplications, are generated by recombinational mechanisms and are discussed in Section 1.4. High copy number repeats, also known as mobile or transposable elements (TEs), are considered to move about using proteins encoded either by themselves or in trans by another mobile element (Table 1.1). These elements have amplified over the course of evolution and attained copy numbers ranging from several tens to over a million in mammalian genomes. TEs may be characterized on the basis of several aspects, including whether or not the element is autonomous, presence or absence of terminal repeats, and the mechanisms by which the elements move. Table 1.1 Human TE types, copy numbers, genomic coverage, and mutation occurrence Type/family Copies per haploid human genome (X1000)" Genomic coverage (%)a Human mutations documented? SINEs 1558 13.14 Alu 1090 10.60 22 MIR 468 2.54 LINEs 868 20.42 L1 516 16.89 13 L2 315 3.22 L3 37 0.31 LTR elements 443 8.29 ERV class I 112 2.89 ERV class II (ERV-K) 8 0.31 ERV class III (ERV-L) 83 1.44 MaLR 240 3.65 SVA 3C 0.15 4 DNA elements 294 2.84 Total 44.84 39 aTaken from International Human Genome Sequencing Consortium (2001), unless otherwise noted bFrom Chen et al. (2005) cFrom Wang et al. (2005) D N A transposons, no longer mobile in mammals, are exemplified by the P-4 elements in Drosophila (Pinsker et al. 2001). Active elements of this type move by a cut-and-paste mechanism (Kazazian 2004). Autonomous elements encode their own transposase protein, which binds in a sequence-specific manner to the terminal inverted repeats flanking the element and cleaves the DNA, excising the element (Miskey et al. 2005). Non-coding D N A with similar flanking inverted repeats is also susceptible to cutting and pasting by the same proteins. In rice, multiple D N A transposons exist, including autonomous Pong and non-autonomous mPing and Mutator-like elements (Jiang et al. 2003; Jiang et al. 2004). Proliferation of Mutator-like non-autonomous elements harboring coding-competent genie sequence has also been documented (Jiang et al. 2004). In mammals, these elements are no longer functional. However, their recombinase functions persist in the co-opted R A G genes used in V(D)J recombination (Brandt and Roth 2004; Schatz 2004). Retroelements, in contrast to D N A transposons, move by a copy-and-paste mechanism (Kazazian 2004). R N A intermediates are reverse transcribed into D N A using a reverse transcriptase protein. Similar to D N A transposons, autonomous retroelements code for their own reverse transcriptase, while non-autonomous elements depend on this protein in trans. Several broad classes of retroelements exist, including long interspersed nuclear elements (LINEs), short interspersed nuclear elements (SINEs), pseudogenes, and elements with long terminal repeats (LTRs) (Kazazian 2004). Approximately 100 families of LTR-containing elements have been found in humans, varying in length from several hundred base pairs in size for solitary LTRs to full length elements as long as 10 kb (Jurka 2000; International Human Genome Sequencing Consortium 2001). These include endogenous retroviruses (ERVs), which are presumed to have resulted from 5 germline infections by exogenous viruses, LTR retrotransposons, and repetitive elements with an LTR-like structure for which no corresponding full-length structure has been identified (Mager and Medstrand 2003; Medstrand et al. 2005). Approximately 85% of LTR-retroelement insertions exist in the human genome as solitary LTRs, a result of recombination between the terminal repeats (International Human Genome Sequencing Consortium 2001). ERVs are so named due to their structural similarity to the integrated provirus form of exogenous retroviruses (Figure 1.1). The flanking LTRs contain necessary regulatory motifs for their transcription in three regions, termed U3, R, and U5, described further below. The internal sequence encodes the proteins necessary for their retrotransposition. Both autonomous ERVs and LTR retrotransposons increase their copy number through mRNA intermediates which are reverse transcribed and reinserted into the host genome, and their overall genomic organization includes several features related to their life cycle (Wilkinson et al. 1994). Just 3' of the upstream LTR are a tRNA primer binding site, which primes reverse strand synthesis, and a packaging signal which interacts with the nucleocapsid protein. The internal sequence of these elements includes gag and pol genes, which code for a nucleocapsid protein, a protease, RNAse H, reverse transcriptase, integrase, and other genes. Just 5' of the downstream LTR is a poly-purine tract. Finally, the LTR begins and ends with TG and CA dinucleotides, which are important for insertion. Some ERVs have an additional env gene, which codes for an envelope protein and allows ERVs to form infectious particles that can escape the host cell and reinfect adjacent cells. However, it should be noted that in humans the vast majority of these elements are defective, with mutations in some, usually all, of their internal sequences. No disease-causing ERV insertions have been found in humans, 6 although several loci are polymorphic for presence or absence of an E R V in humans (Turner et al. 2001; Bennett et al. 2004; Belshaw et al. 2005). As with all retroviruses, insertions of ERVs are flanked by short tracts of identical sequence, called a target site duplication (TSD), usually 4-6 bp in length. Figure 1.1 Full length endogenous retrovirus-like elements. A. Full-length HERV-H, as described by Jern et al. (2005). HERV-H has genomic organization and genes related to those of infectious retroviruses, as well as canonical pol-II transcriptional signals. This suggests that it has been an autonomous element that entered the primate gerinline as an infection by an exogenous virus. PBS and PPT are primer binding site and polypurine tract, respectively. B. HUERS-P1 element, first described by Harada et al. (1987). HTJERS-P1 element lacks discernable open reading frames, although having presumptive pol-II transcriptional signals in its LTRs, and therefore is presumed to be non-autonomous. Another class of LTR-containing elements exists whose internal sequence bears little or no resemblance to that of exogenous viruses. These elements include the Mammalian apparent LTR retrotransposons (MaLRs) and so-called medium-reiterated 4 elements (MER4s) which lack internal similarity to retroviral genes (Smit 1993). However, these elements do contain the obligatory LTRs with regulatory motifs as well as polypurine tracts, which leaves open the question of how these elements have been 7 mobilized. Active full-length LINE elements are typified by the L I family (Figure 1.2). These elements are transcribed from an internal R N A polymerase II (pol II) promoter (Swergold 1990; Tchenio et al. 2000; Yang et al. 2003; Athanikar et al. 2004) and have two open reading frames (ORFs), which encode a nucleic acid binding protein, a reverse transcriptase, and an endonuclease; these proteins are necessary for their own transposition (Kazazian 2004). These elements terminate with a polyadenylation signal and poly-A tract. The origin of LINE elements is unknown, however many classes of eukaryotes contain them, including mammals, fish, invertebrates, plants, and fungi (Furano 2000). L i s exhibit a marked cis preference, which means that proteins encoded most often act only on the mRNA that encoded them (Wei et al. 2001). In addition, however, L i s have also been shown to mobilize other R N A species, for example processed mRNAs and SINEs in human (Esnault et al. 2000; Dewannieux et al. 2003). Antisense promoter activity from the 5' UTR has also been reported (Nigumann et al. 2002). Species of mRNA mobilized by L i s usually have a TSD 7-20 bp in length. Promoter / 5' UTR ORF1 ORF2 3 ' U T R 13-21 83-101 472-477 572-577 YY1 RUNX3 SOX SOX I I Antisense promoter Figure 1.2 LI structure. The overall genomic organization of the currently active LI (Hs) consists of a 5' UTR/promoter, two open reading frames (ORF1 and ORF2), and a short 3' UTR, which terminates in a canonical polyadenylation signal followed immediately by a poly-A tract. The promoter region has recognized binding sites for YY1, RUNX3, and SOX-family transcription factors (Swergold 1990; Tchenio et al. 2000; Yang et al. 2003; Athanikar et al. 2004). An antisense promoter has been described (Nigumann et al. 2002). 8 Active SINE elements are typified in humans by the Alus and S V A elements. Alus are non-protein coding, R N A polymerase Ill-driven, 7SL RNA-derived dimeric elements (Ullu and Tschudi 1984) (Figure 1.3). Alus number in excess of one million copies in the haploid human genome (International Human Genome Sequencing Consortium 2001) and are still actively retro transposing in the primate lineage. Their current amplification rate, estimated at one in 200 live births (Deininger and Batzer 1999), is 100-fold lower than at the peak of their activity (Shen et al. 1991). Elements polymorphic for presence or absence in the human population, which number approximately 1000 in the average human (Bennett et al. 2004), have also demonstrated usefulness in distinguishing relationships of human populations (Batzer and Deininger 2002). In addition to Alus, primate genomes contain a family of mammalian-wide fRNA-derived SINEs called MIR, which are older than Alus and are not known to be transcribed in humans (Smit and Riggs 1995). Other fRNA-derived SINEs are active in mice (Dewannieux and Heidmann 2005). ~50-bp similar regions Figure 1.3 Typical Alu element of ~300 bp. Similar regions share ~70% identity. In addition to Alu elements, SVAs comprise another relatively numerous superfamily of SINE elements. Numbering 2762 in the haploid human genome (Ono et al. 1987; Wang et al. 2005), these elements are believed to be confined to the hominoid 9 primates, indicating a relatively recent evolutionary origin (Kim et al. 1999; Wang et al. 2005). They consist of a hexamer repeat, homologies to inverted Alu elements, a variable number of tandem repeats, and a deleted partial copy of an E R V - K element including the terminal part of an env gene and a partially deleted LTR (Figure 1.4). SVAs end with a polyadenylation signal and poly-A tract (Ono et al. 1987; Zhu et al. 1992; Shen et al. 1994; Wang et al. 2005). The fact that S V A elements contain a major portion of an E R V - K LTR suggests that these active elements may have LTR-like effects. Furthermore, mRNA evidence exists supporting a role for these elements as alternative promoters, for example the hyaluronoglucosaminidase 1 and the G protein-coupled receptor M R G X 3 genes (University of California Santa Cruz Genome Browser, http: //genome. uc sc. edu). ( C C C T C T ) n Alu Alu p o - 270) (135 - 260) VNTR HERVK10 Aenv + LTR AU3/R 500 1000 I 1500 Figure 1.4 Structure of a typical SVA element, found at human chromosome 13ql4.11. SVAs consist of a tract of C C C T C T hexamer repeats, two regions homologous to Alu elements, a region containing a variable number of tandem repeats (VNTR), and a partial HERVK10 env gene and partial LTR, ending with the polyadenylation signal and an immediate poly-A tract. LI-driven retro transposition is targeted to T T / A A A A sites, which are widely dispersed through mammalian genomes (Jurka 1997). The process is known as target primed reverse transcription (TPRT), reviewed in Kazazian (2004), and begins with opposite-strand nicking at the insertion site, uncovering a short poly-T tract complementary to the mRNA to be reverse-transcribed. The mRNA poly-A tail anneals 10 to the poly-T tract, which then serves as a primer for reverse transcription (Figure 1.5). After insertion, new elements segregate as Mendelian genes in the population. The likelihood of any given insertion reaching fixation in a population is very small. 5'i Target Site l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l 5' T a) First strand cleavage f cleavage c) Second strand 5-i Target Site | i i i n m n i i - ' H i y ^ l i i i M i i i n m 5" d) Integration 1 SI) e) DNA synthesis TSI) New insert flanked by target site duplications Figure 1.5 Target-primed reverse transcription (TPRT). Taken from Ostertag and Kazazian (2001). Due to the copy-and-paste strategy employed by retroelements in their amplification, new retroelement insertions are ideally identical to their ancestor element. Independent mutations occurring in an individual element either during or after 11 retrotransposition introduce variation which is then faithfully inherited by derivative copies of the element. This process results in an increasing genomic population of elements marked by diagnostic mutations. These mutations may then be exploited to infer family relationships of accumulated retroelements (International Human Genome Sequencing Consortium 2001). Furthermore, the likely sequence of the ancestral elements can be reconstructed from sequence alignments of distributed copies of the element. Divergence from this consensus element can then be computed and, assuming a molecular clock, the approximate age of each element may be computed. This type of analysis has been described elsewhere (Smit 1993). The molecular clock is usually calibrated using fossil evidence whose age is calculated from radioactive dating of fossils based on the apparent age of the rocks where the fossils are found (Goodman et al. 1998). 1.2.3 Mutagenic roles of transposable elements As early as Barbara McClintock's experiments with D N A transposons in corn, an appreciation of the 'gene-controlling' effect of these 'jumping genes' began to take root (McClintock 1950; McClintock 1956). In those experiments, it was noted even in physical examination of chromosomes that new insertions could drastically alter local chromosomal structure and these could account for alterations in phenotypic characteristics such as kernel color. Mutagenic roles of TEs may be grouped into several types. Most basic of all, insertional mutagenesis involves disruption of a conserved and functionally important region of DNA. Perhaps because they are more readily analyzed, most well-studied cases of insertional mutagenesis involve disruption of a coding exon of a transcribed gene which then introduces a stop codon or frame-shift resulting in a prematurely terminated or non-functional transcript. Examples of this type of mutagenesis reported in the 12 literature include inactivation of the human cholinesterase gene by an Alu insertion (Muratani et al. 1991) and disruption of the Factor VIII gene by an L I element causing hemophilia A (Kazazian et al. 1988). More examples are described by Deininger and Batzer (1999) and reviewed by Chen et al. (2005). As a variation on this theme, in one report a sequence believed to have been 3'-transduced by an S V A element was found to have disrupted exon 5 of the alpha spectrin gene, resulting in exon skipping (Hassoun et al. 1994; Ostertag et al. 2003). Several more subtle regulatory roles exist for TEs, usually related to the structure of the consensus element. For example, although the phenomenon is apparently fairly rare, mutations in intronic antisense Alu 3' ends can lead to generation of an efficient splice acceptor site which may result in disease (Sorek et al. 2002; Lev-Maor et al. 2003; Sorek et al. 2004). L i s , on the other hand, have recently been shown to act fairly universally as transcriptional rheostats, reducing transcription of genes they are found in (Han et al. 2004). This activity is believed to be due to the A-rich consensus element, which is believed to cause the pol-II holoenzyme to fall off its template with high frequency. Reduction in this A-richness while conserving the protein sequence of the element resulted in highly efficient transcription (Han and Boeke 2004). Furthermore, presence of A-rich LI sequence in introns of genes was correlated with overall reduction in transcription efficiency. On the other hand, L i s integrating into introns in a direction antisense to the gene's direction of transcription have a demonstrated polyadenylation activity (Perepelitsa-Belancio and Deininger 2003; Han et al. 2004), resulting in reduction of transcription in either orientation by intronic L i s . Intronic L i s have also been linked to disease (Kimberland et al. 1999). 13 Another type of mutagenesis related to the element's sequence is that posed by ERVs and their LTRs. As described above, active elements of this type code for several genes related to their life cycle. In order to produce correct amounts of each protein, these elements often splice out part of their coding sequence, requiring the presence of functional splice donor and acceptor sites in the full-length element (Rabson and Graves 1997). Mutations due to these splice sites have been demonstrated in mice (Maksakova et al. 2006). More importantly than donation of splicing motifs by full-length ERVs, LTRs harbor transcriptional control elements including fully functional promoters and polyadenylation signals. The general structure of LTRs has been studied extensively (Temin 1982; Rabson and Graves 1997). A classical LTR consists of three regions, termed U3, R, and U5. The U3 region extends from the 5' end of the LTR or proviral copy through the promoter to the start of transcription (Figure 1.1). Together with the R region, the U3 region does double duty as the 3' untranslated region (UTR) of retroviral transcripts. The R region extends from the start of transcription to the polyadenylation site of viral transcripts and contains the polyadenylation signal. Lastly, the U5 region, with the R region, forms the 5' UTR of the viral transcript. The most fruitful mammalian examples of LTR mutagenesis come from inbred strains of mice, in which 10 percent of characterized new mutations are due to insertional mutagenesis as a result of E R V or LTR insertions (Maksakova et al. 2006). This is often associated with intronic localization (Baust et al. 2002) in the same transcriptional orientation as the gene, which often leads to premature polyadenylation (Maksakova et al. 2006). The mutagenic nature of LTR polyadenylation motifs has been used in gene 14 trapping experiments, in which constructs with a selectable marker and LTR polyadenylation signal were randomly inserted into mouse embryonic stem cells (Friedrich and Soriano 1991; von Melchner et al. 1992; Boeke and Stoye 1997). A total of 28 clones with expression of the selectable marker were used to create transgenic lines of mice and then bred to homozygosity. Eleven of the 28, or approximately 40% of genie insertions proved to be embryonic lethal, highlighting a high-frequency outcome of mutagenesis by polyadenylation: death of the involved cell. Potentially more insidious is the role of ERV insertions as ectopic promoters. LTR promoters consist of a core promoter and regulatory elements composed of arrays of protein binding sites that act as enhancers and repressors to control expression of viral genes (Temin 1982). For example, transcription of the Moloney Murine Leukemia Virus (MLV) is controlled by its LTR, shown in Figure 1.6. In general, the core M L V promoter consists of a T A T A box and cw-acting C A A T enhancer (bound by C/EBP). The more distal enhancer region contains a tandemly duplicated group of transcription factor binding sites. While methylation likely silences many TE insertions (Lavie et al. 2005; Meunier et al. 2005), M L V is silenced by repressor binding sites found upstream of its LTR enhancer. A more complete discussion of transcriptional control by the LTRs of M L V and other exogenous viruses is found in Rabson and Graves (1997). 15 Mo-MLV LTR U3 EIP bHLH CBF NF-1 v GR MCHfcF-(-) <-) 3'»c( repeals Enhancer (+> OEBP TATA Promoter (+) U5 SACTQR A PBS (-) too bp Figure 1.6 Transcription control elements of the MLV LTR. Taken from Rabson and Graves (1997). Long experience with mutational mechanisms in mice, particularly due to spontaneous ERV insertions, has resulted in a large number of these mutations being characterized. The binding sites provided by de novo E R V insertions have frequently been found to cause oncogene activation in mice, functioning either as enhancers or promoters. Relevant mechanisms and frequency have been reviewed by Rosenberg and Jolicoeur (1997). Similarly for humans, an enhancer effect by exogenous lentiviral LTRs has been implicated in two cases of secondary leukemia after gene therapy treatment for X-SCID in 11 individuals (Hacein-Bey-Abina et al. 2003). However, this small number of trials leaves the overall expected frequency of adverse events in a gene therapy context in doubt. In another trial, the hematopoietic systems of 42 immunoablated rhesus monkeys were repopulated with cells having therapeutic insertions of M L V and simian immunodeficiency virus (SIV) vectors (Kiem et al. 2004; Dunbar 2005). Stable, polyclonal, virally marked hematopoiesis was observed, with no secondary leukemias over 6 months to 6 years. In addition to their sense-oriented promoter, enhancer, and polyadenylation 16 effects, there is some evidence that LTRs can be damaging in the antisense direction, upstream of genes or within genes. In one documented case, loss of epigenetic silencing of an antisense intracisternal A particle (IAP) ERV upstream of the agouti gene in mice resulted in ectopic expression of the agouti gene from a cryptic E R V promoter (Morgan et al. 1999). Within introns, aberrant splicing of antisense ERV sequences from cryptic splice signals may be a prominent mutagenic mechanism of ERVs, as also highlighted for IAPs in mice in a recent review (Maksakova et al. 2006). The observation that LTRs are less likely to be found in genes in the antisense orientation than expected by random chance is in agreement with this view (see Chapter 4). A couple of de novo mutagenic roles have been elucidated even for very old TEs. As discussed more fully in terms of mechanism in section 1.4.3, Alus have been shown to engage in Alu-Alu recombination (Deininger and Batzer 1999). The most recent literature describes many examples of this type of event, including mediation of M L L -CBP gene fusion in leukemia (Zhang et al. 2004), deletion in BRCA1 and BRCA2 genes in cancers (Tournier et al. 2004; Ward et al. 2005), and Factor VIII deletions in hemophilia (Nakaya et al. 2004). Finally, for some mutagenic insertions such as those of the hominid S V A retroelement family, the precise mechanism of mutagenesis has not been determined. To date, four cases of de novo mutations due to S V A retroelements have been described. Interestingly, all were within the borders of known genes and are in the same transcriptional orientation as the enclosing gene (Chen et al. 2005). One hint as to a possible mode of mutagenesis comes from the fact that SVAs retain the HERV-K10 endogenous retroviral-derived hormone response element and the core enhancer sequences and a polyadenylation signal derived from the same LTR, suggesting that 17 SVAs can act in a similar way to LTR elements (Ono et al. 1987; Wang et al. 2005). This topic is addressed in Chapter 4. 1.2.4 Relationships between initial and long-term distributions of TEs It has been observed that for some elements, for example Alus, the final genomic distribution does not correspond to that of newly-inserted active elements of the same type (International Human Genome Sequencing Consortium 2001) (See also Chapter 2). In the case of Alus, their consensus T T A A A A insertion site is expected to be found more often in regions of high A T sequence content and, indeed, recently inserted Alus tend to be located in AT-rich regions, similar to the pattern seen for LI elements (Smit 1999; International Human Genome Sequencing Consortium 2001). However, the vast majority of Alus are found in GC-rich regions. Several theories have attempted to explain this disparity. Pavlicek et al (2001) noted that, in spite of using the same target site, the observed long term distributions of Alus and L i s were biased to different GC content isochores. In their data set, the presumed slightly older AluYb8 subfamily was more skewed to higher GC isochores than the slightly younger AluYa5 subfamily. Therefore, they proposed that the GC-richness of Alu elements makes them more stable in regions where the surrounding GC content is similar to that of the Alu consensus, and that excision by an unknown mechanism happens more frequently in high-AT isochores (Pavlicek et al. 2001). Others have hypothesized that Alu elements are selectively retained in GC-rich regions because of a functional benefit to genes, which reside in high-GC regions. For example, Britten cites individual Alu elements from earlier literature conferring functional binding sites for various proteins to nearby genes (Britten 1997). Schmid 18 hypothesized that Alus might be involved in chromatin remodeling and signaling of double-stranded RNA-dependent protein kinase in response to cell stress, conferring a selective advantage for having Alus in transcribed regions (Schmid 1998). While these studies are tantalizing and suggest selective advantage of individual Alus, no study since that time has demonstrated an overall selective advantage for accumulation of Alus in GC-rich regions. Instead, the developmentally critical HoxD gene cluster is almost devoid of retroelements (International Human Genome Sequencing Consortium 2001), suggesting that some classes of genes may need to exclude such sequences from their environment to ensure proper function or regulation. A more neutralist third hypothesis proposes that Alus are maintained in GC-rich regions because deletions are unlikely to be precise and deletions of these elements in gene-rich regions would likely also involve important adjacent regulatory sequence (Brookfield 2001). While more satisfying in that it attempts to explain the Alu distribution without invoking a functional role, rates of deletion in gene-rich vs. gene-poor regions in primates have not been conclusively assessed. Furthermore, given that only five percent of mammalian genomes is estimated to be under purifying selection (Mouse Genome Sequencing Consortium 2002) and therefore vulnerable, it is unlikely that this explanation alone can account for the massive accumulation of Alus in gene-rich regions. A fourth mechanism theorized to contribute to the relative paucity of Alus in gene-poor, high-AT regions is Alu-Alu recombination. Closely-spaced Alu pairs are found only occasionally in the human genome (Lobachev et al. 2000; Stenger et al. 2001), possibly because of clearance of these elements through the mechanism of inverted repeat (IR)-mediated recombination (Leach 1994). Later studies have linked this 19 phenomenon to sister chromatid exchange (Nag et al. 2005). In addition, unequal homologous recombination results in loss of the sequence separating closely spaced directly repeated Alus (Stenger et al. 2001). Even Alus up to 20% divergent have been found to recombine efficiently (Lobachev et al. 2000). That this process is ongoing is evidenced in its observed involvement in human disease, discussed above. This mechanism provides an additional explanation for the enrichment of Alus in GC rich regions without requiring a functional role. While the above theories address likelihood of fixation of inserted elements, some interesting recent work motivated by the use of retroviral vectors in gene therapy has focused instead on mechanisms involved at the time of insertion. For example, work using unselected in vitro integrations of HIV and HIV-based vectors consistently demonstrated a propensity to integrate in transcribed regions, with higher frequency in highly transcribed genes (Schroder et al. 2002; Mitchell et al. 2004; Barr et al. 2005). M L V , on the other hand, has a marked preference to integrate into the start sites of more active genes (Wu et al. 2003), and avian leukosis virus (ALV) demonstrated a weaker, though highly significant, preference for transcribed regions (Mitchell et al. 2004; Barr et al. 2005). The question arises why the different viruses target active genes, and then with varying locations within genes. Early experiments in Swiss mouse cells found that the majority of M L V insertion sites were sensitive to a micrococcal nuclease and DNAse I, suggesting that viral integrations chiefly target accessible DNA, which is found in regions of open chromatin (Panet and Cedar 1977). While access to targets may well partially explain integration targeting, it fails to explain the additional marked preference of M L V for 5' regions of genes. Instead, a tethering model whereby interactions between 20 the viral preintegration particle and host factors bound to D N A facilitate targeting of integrations to specific regions within open chromatin has been proposed (Bushman 2003; Bushman et al. 2005). In such a model, M L V might be tethered by transcription factors, while HIV might interact with proteins that bind within transcription units. One candidate tethering factor has been identified for HIV (Ciuffi et al. 2005). Additional evidence for this phenomenon comes from the recent discovery of symmetrical base pair profiles around sites of insertion of HIV-1, A L V , and M L V (Holman and Coffin 2005). It should be noted, in any case, that studies of in vitro insertions represent insertions before they have a chance to be tested during organismal development. Only after escaping purifying selection during development and the lifetime of an organism do germline mutant alleles have a chance to segregate in the population and attain a small chance of spreading to fixation. 1.3 Neutral or beneficial roles for TEs in the transcriptome 1.3.1 Regulatory motifs donated by TEs In addition to a potent role as mobile genomic mutagens, there has been a growing appreciation for the positive roles TEs can fulfill (Kidwell and Lisch 1997). One early role elucidated for TEs was as the parotid-specific enhancer of the human amylase gene (Ting et al. 1992). In that investigation, a 700 bp fragment approximately 300 bp upstream of the transcription start and derived entirely from a human endogenous retrovirus E (HERV-E) LTR was sufficient to confer salivary expression on a reporter gene in transgenic mice. Curiously, an LTR element has also been found to act in the opposite role as a strong upstream repressor of annexin A5 transcription (Carcedo et al. 21 2001). Many more examples of LTRs acting as alternative promoters of cellular genes exist. A growing body of literature describes genes in many roles under the control of ERV LTRs (For reviews, see Leib-Mosch et al. 2005; Medstrand et al. 2005)(see Chapter 3). An early investigation identified an ERV9 LTR that acts as a tissue-specific promoter of the zinc finger gene ZNF80 and drives expression in several hematopoietic cell lineages (Di Cristofano et al. 1995). An ERV9 element in the human globin locus control region has also been shown to participate in expression of downstream genes, likely by participation in chromatin remodeling (Yu et al. 2005). Several examples of HERV-E LTRs acting as alternative promoters, including involvement in MIDI , apolipoprotein CI and endothelin B receptor expression, have been identified as well (Medstrand et al. 2001; Landry et al. 2002). More recently, an LTR of the E R V - L superfamily has been shown to form the dominant promoter of the human betal,3-galactosyltransferase 5 gene in humans (Dunn et al. 2003). This promoter was found to be more conserved than expected by chance, suggesting purifying selection preserving these retroviral sequences (Dunn et al. 2005). This example is instructive, as the orthologous mouse gene is also expressed in colon despite the lack of an LTR promoter, leading to the conclusion that the insertion of this E R V has been co-opted because it provided useful motifs in the approximately correct position rather than because it is essential. This example may also suggest external control by a separate colon-specific enhancer. Finally, a genome-wide bioinformatic survey showed that most TE types have some basal capacity to form 5' transcriptional start sites, presumably by contributing pre-existing promoter-related sequences or by evolving them in situ (Dunn et al. 2005, See also Chapter 3). However, LTR elements upstream of genes in the same transcriptional 22 orientation as the gene form the transcriptional start sites of genes far more often than other TE types, relative to their local genomic density (Figure 1.7). LTRs that are antisense to the gene transcriptional direction form the 5' ends of genes next most often, suggesting a significant, though secondary, role for transcription factor binding sites donated by the LTR as a nearby enhancer or downstream promoter. 0.01400 -. 0.01200-0.01000-c o 0.00800 -« c \ <J CO 0.00600 -L i . 0.00400 -0.00200 -0.00000 -El Sense H Antisense JM Pi:? H m SINE LINE LTR TE class DNA Figure 1.7 Orientation of TEs that contain human gene transcriptional start sites. TEs within the genomic region 5kb upstream and 5kb downstream of human RefSeq gene transcriptional start sites were grouped by class and orientation with respect to the direction of gene transcription. The fractions of sense and antisense TEs that contain transcriptional start sites are depicted for each class by gray and black bars, respectively. Taken from Dunn et al (2005). Most of the above-discussed roles for TEs involve LTRs in control of transcription, but this balance likely reflects some bias in the current research interests of the groups involved. TEs have also been shown to perform other neutral or beneficial roles. As mentioned above, L i s have been shown to have antisense promoter activity. This has been shown to involve several cellular transcripts (Nigumann et al. 2002). Furthermore, LTRs have been shown to donate polyadenylation signals to cellular genes. In one example, E R V - H LTRs provide polyadenylation signals to the HHLA2 and 3 genes (Mager et al. 1999). The absence of these LTRs in baboon was associated with use 23 of alternate polyadenylation signals. Another example involves polyadenylation of receptor tyrosine kinase FLT4 and other transcripts by human E R V - K LTRs (Baust et al. 2000). Lastly, an array of several retroelements has been shown to exert a modulatory effect on transcription and translation efficiency of the zinc finger gene ZNF177 (Landry etal. 2001). The above considerations, taken together, are strong evidence of a neutral or positive role for some TEs, particularly LTRs, and motivated a bioinformatic survey of the contributions of TEs to the transcripts of protein-coding genes, as reported in Chapter 3. 1.3.2 Protein domains donated by TEs In addition to roles in transcription control, TEs have also been demonstrated to have contributed to mammalian proteomes. Perhaps the best known example is that of the recombination activating (RAG) genes involved in V(D)J recombination, which are derived from D N A transposons (Reviewed in Brandt and Roth 2004; Schatz 2004). The R A G genes are found in jawed vertebrates and mediate precise, site-specific combinatorial joining of gene segments making up antigen receptors in T and B cells. In addition, E R V sequences have also been found to perform useful functions. In two known and completely unrelated cases, the fusogenic properties of coding-competent retroviral env genes from E R V - W and ERV-FRD have been co-opted as two different syncytin genes, both with a role in placenta formation (Mi et al. 2000; Renard et al. 2005). These and other potential roles of retroviral-derived proteins in health and disease are discussed by Bannert and Kurth (2004). 24 1.4 Stability of repetitive sequence 1.4.1 Assumptions of stability and use of retrotransposed sequence as population markers Insertions of retroelements have undergone intense scrutiny as a destabilizing influence in mammalian genomes. In particular, insertions of recent families of SINEs and LINEs in primates have been shown to be associated with deletions and other rearrangements upon insertion (Gilbert et al. 2002; Symer et al. 2002; Callinan et al. 2005). Furthermore, as mentioned above, high copy number genomic elements may cause disease by homologous recombination with each other (Deininger and Batzer 1999). New insertions of retroelements that are at worst mildly deleterious segregate as Mendelian alleles in the population and have a small chance of reaching fixation. Once fixed, elements are generally assumed to be stable, except when involved in infrequent rearrangements. As a result, assessments of relative activity of retroelements have assumed that presence of an element at a given site is an unambiguous indication of insertion (Liu et al. 2003). A corollary of this assumed unidirectionality of retroelement insertions with no known mechanism for precise deletion is that genomic retroelement loci may be assumed identical by descent rather than identical by state. This property makes active families of Alu and LI elements ideal for use in studying relationships between human populations (Perna et al. 1992; Sheen et al. 2000; Carroll et al. 2001; Roy-Engel et al. 2001). For example, 20 to 30 percent of insertion loci of some active Alu families are polymorphic for presence or absence of the element between human populations (Carroll et al. 2001; Roy-Engel et al. 2001). Similar analyses have also been used in the resolution of primate phylogeny. For example, one study used evidence from the AluYe5 family to show 25 strong support for a sister grouping of chimpanzees and humans (Salem et al. 2003b). 1.4.2 .A role for DNA double-strand break (DSB) repair in creating de novo insertions, deletions, and tandem duplications While insertion of pol-II transcribed retroelements has the potential to explain many genomic regulatory changes, many more sequence differences between genomes may be explained by the paradigm of D N A DSB repair. The association of single gene mutations in this pathway with known diseases (for review, see Thompson and Schild 2002) and the feasibility of studying DSB repair in cell culture systems has made it possible to investigate many of the most important proteins and their mechanisms. Double strand breaks in DNA, induced by gamma rays or free radical insult, are repaired by one of two main mechanisms. One is slower and involves similarity between the sequences to be joined, while the other is faster and homology-independent. The interactions between these pathways have been characterized as competitive in eukaryotic cells (Prudden et al. 2003), and resolution of a DSB sometimes involves both mechanisms. Before repair begins, however, broken and damaged D N A ends are trimmed by an endonuclease complex (Helleday 2003). The fast, homology-independent mechanism of DSB repair, commonly termed non-homologous end joining (NHEJ), initiates with the binding of a K u heterodimer in a ring around each broken D N A end, stabilizing it (Walker et al. 2001). The DNA-bound Ku heterodimers are then bound together and the D N A ends trimmed (Helleday 2003). Finally, ligases rejoin the two ends. The slower, homology-driven mechanism of DSB repair is believed to begin with a 5' to 3' peeling back or resectioning of the D N A by an unknown exonuclease, exposing a 3' single-stranded D N A (ssDNA) end. Frequently, exposure of several hundred base 26 pair repeats such as Alus in two 3' ssDNA ends in mammalian cells results in repair by a mechanism known as single-strand annealing (SSA) (Elliott et al. 2005). SSA is an error-prone mechanism which results in loss of one of the flanking repeats and the intervening sequence. In the absence of long similar sequences, shorter sequences are also used, but less frequently, and the precise mechanisms are uncertain (Sankaranarayanan and Wassom 2005). As an alternative to SSA, homologous recombination (HR), which involves BRCA1, BRCA2, and RAD51 proteins, may occur. In this case, RAD51/ssDNA filaments invade nearby D N A duplexes and pair with homologous D N A (Helleday 2003). The sister chromatid, available during the S and G2 phases of the cell cycle, is the homologous D N A duplex most often used as a template for repair (Johnson and Jasin 2000), rather than the homologous chromosome, use of which could result in loss of heterozygosity (Moynahan and Jasin 1997). Upon strand invasion, a Holliday junction is formed and D N A synthesis occurs, often continuing beyond the original site of D N A breakage. In any case, final resolution of the break may occur by NHEJ, secondary SSA, or reinvasion of the original duplex by the nascent D N A strand at the homologous location beyond the site of the original break. Resolution by secondary NHEJ or SSA has the potential of causing deletions or tandem D N A insertions, while secondary SSA or reinvasion of the original duplex may result in error-free repair. Finally, aberrant template choice, for example in the case of D N A breakage at Alu elements or other ubiquitous motifs, may result in ectopic sequence duplication (for review, see Helleday 2003). Chapter 5 discusses observations of the absolute rate with which retroelement insertions actually revert or undergo precise deletion, presumably by a D N A DSB 27 homologous repair mechanism. The relative paucity of these events shows that identity by descent is a relatively safe assumption for retroelement loci compared across species. It also addresses the role of homologous direct repeats in sequence removal from primate genomes. 1.5 Repeat finding methods While the goal of this thesis was to understand the interaction of repetitive elements, it depended heavily on repeat annotation provided by RepeatMasker (A.F. A . Smit and P. Green, unpublished) as tracks in the UCSC Genome Browser. RepeatMasker makes use of the Repbase libraries (Jurka 2000) to iteratively mask genomic sequence, excising fully embedded repeats and allowing more confident identification of the targeted repeat (A.F. A . Smit and P. Green, unpublished). MaskerAid (Bedell et al. 2000) is a suite of perl scripts that adapts WU-BLAST (W. Gish, unpublished) for use with RepeatMasker, functionally replacing the cross_match aligner. MaskerAid increases the speed of RepeatMasker analysis dramatically, by 40 fold at most RepeatMasker sensitivity settings, while identifying repeats with nearly identical sensitivity and specificity (Bedell et al. 2000). This reflects the fact that both methods rely on pairwise sequence alignment of genomic sequence with consensus sequences, typically from Repbase Update (Jurka 2000), to identify repetitive regions in genomes. RECON, by contrast, uses a tunable, heuristic analysis of results of a self-BLAST to perform de novo definition of repeat boundaries and thus repeat families (Bao and Eddy 2002). The algorithm is tunable on at least two levels, that of the sensitivity of the B L A S T search it is based on and the 'willingness' of the heuristic analysis to split elements up (Bao and Eddy 2002; Holmes 2002). This and related methods of 28 constructing repeat family consensus elements can make a valuable contribution to analysis of newly sequenced genomes. RepeatScout represents a further development on the R E C O N concept (Price et al. 2005). RepeatScout uses overrepresented short sequences as seeds for local pairwise alignments, which then are reconstructed into longer repeat consensus sequence. In testing, this de novo repeat finding method identified a more complete set of rodent repeat families than had been included in Repbase Update (Jurka 2000). However, repeat identification by masking with RepeatScout-generated human libraries found less repeats than masking with Repbase libraries. This observation was attributed to the fact that the human genome has been better studied, allowing for many years of curation of human repeat families. In summary, all these methods are limited in that they rely on pairwise alignment methods to find repeats. Repeats that undergo many short insertions or deletions, despite being recognizable by eye, are unduly penalized for being broken up. It seems clear that a better model of sequence evolution is required before repeat finding can reach optimal sensitivity. In the interim, repeats found by RepeatMasker and Repbase libraries have provided an opportunity to assess the nature of the effects of transposable elements on their host genome. 1.6 Thesis objectives and chapter summaries Repetitive sequence is ubiquitous in mammalian genomes and has an array of consequences for the organism, both positive and negative. In some cases, positive roles for repetitive sequence are related to their mutagenic role. For example, binding sites donated by E R V LTRs can function as transcriptional enhancers, repressors, and polyadenylation signals. While these functions can interfere with the function of nearby 29 genes, in many cases they can also provide regulatory diversity. While a few cases of neutral or positive roles have been identified for LTRs, there are likely many more. Nonadjacent repeated sequences, on the other hand, can have a different role. Whether in the form of high-copy repeats or short random nonadjacent segments of identity, these sequences can function as substrates for DNA repair. While the potential for deletion of tumor suppressors and other genes is obvious, nonadjacent repeats may also have a positive function in genome size attenuation. The main goal of this thesis work was to use automated sequence analysis and global statistical analyses of mammalian, primarily human, genomic repeat distributions to gain understanding of the roles of repetitive sequence in defining organisms at the genetic and hopefully also phenotypic levels. As the project progressed, more and more information became available that increased our ability to ask fundamental questions about these roles. Time was spent at the outset of the project developing methods and algorithms; however, as more data became available, the data formats and repositories evolved in response. The availability of a draft of the human genome sequence provided the positive stimulus for the development of the various genome browsers as well as long term choices being made on data formats. The information infrastructure and tools made available with the data have considerably aided in this analysis. Subsequent availability of a draft of the mouse genome sequence enabled us to use comparative approaches to assess TE involvement in the human and mouse transcriptomes. At the same time, availability of raw sequencing traces from multiple human sources enabled others to assess the levels of repeat polymorphism present in the human. Using these published data sets, we were able investigate detrimental impacts of retroelement families active in humans and compare them to the projected detrimental impacts of older, inactive 3 0 families. Finally, availability of sequence traces from Rhesus monkey allowed us to assess precise deletion of retroelements in the human and chimpanzee lineages. Chapter 2 describes our initial analyses of the draft sequence of the human genome. The analyses performed were essentially collations of repetitive sequence and assessment of their location with respect to genomic features like sequence composition and genie positions. This analysis showed that TEs of different ages localize to different regions of the human genome and that LTR elements demonstrate orientation bias up to 5kb upstream and downstream of transcribed regions. Chapter 3 describes our analysis of TEs in transcripts. Mapping of human and mouse protein coding transcripts and TEs were compared to find transcripts that contained TE sequence. Databases of gene classification information were then developed and classification of human and mouse genes performed to determine which classes of genes had TEs as part of their transcripts more often. The same classes of genes in both human and mouse, such as those with more organism-specific functions, tended to be permissive for the presence of TE sequence in transcripts. Highly conserved genes and genes with important housekeeping or developmental functions were less permissive. Chapter 4 reviews our work on TE directional biases in human and mouse transcribed regions. Different families of LTR elements showed widely varying retention patterns within transcribed regions. S V A retroelements, which retain a partial LTR in their consensus, also demonstrated an LTR-like pattern, suggesting that TEs transcribed by RNA polymerase II (pol II) exert varying effects upon insertion, depending on the sequence of the element. Chapter 5 is concerned with analysis of nonadjacent repeated sequence and its 31 role in recombination and deletion. Retroelement insertions, normally assumed to be stable with no known mechanism for precise deletion, are shown to be deleted precisely in some cases, most likely due to a mechanism involving D N A double strand break repair and the flanking short tracts of identical sequence. Analysis of random deletions showed that a large fraction of these events are also mediated by short nonadjacent tracts of identical sequence. 32 Chapter 2: Retroelement distributions in the human genome A version of this chapter has been published: Medstrand, P.*, L . N . van de Lagemaat*, and D.L. Mager. 2002. Retroelement distributions in the human genome: variations associated with age and proximity to genes. Genome Res 12: 1483-1495. * these authors contributed equally to this work I performed all data analysis and wrote sections of the paper. P. M . and D. L. M . performed postprocessing of the data in Figure 2.2 and wrote a significant share of the paper. 33 2.1 Introduction Since Barbara McClintock discovered transposable elements (TEs) in maize (McClintock 1956), it has become well established that such elements are universal. While there are examples of both loss and increase of host fitness due to the activity of transposable elements, their population dynamics are far from being understood, and the forces underlying their genomic distributions and maintenance in populations are a matter of debate (Biemont et al. 1997; Charlesworth et al. 1997). The prevailing view is that TEs are essentially selfish D N A parasites with little functional relevance for their hosts (Doolittle and Sapienza 1980; Orgel and Crick 1980; Yoder et al. 1997). According to this hypothesis, the interaction of TEs with the host is primarily neutral or detrimental and their abundance is a direct result of the ability to replicate autonomously. It is generally accepted that selection is the major mechanism controlling the spread and distribution of TEs in natural populations of model organisms (Charlesworth and Langley 1991). While the exact mechanisms through which selection acts are controversial, the processes controlling transposition involve selection against the deleterious effects of TE insertions close to genes (Charlesworth and Charlesworth 1983; Kaplan and Brookfield 1983) and selection against rearrangements caused by unequal recombination (ectopic exchange) in meiosis (Langley et al. 1988). More recently, the ubiquitous nature of TEs has gained increasing attention and it is now becoming accepted that TEs give rise to selectively advantageous adaptive variability which contributes to evolution of their hosts (McDonald 1995; Brosius 1999). However, the mechanisms responsible for maintenance, dispersion, fixation and genomic clearance of TEs remain largely unknown. While most work on TEs has focused on model organisms, sequencing of the human genome has revealed that nearly half of our D N A is derived from ancient TEs, 34 mainly retroelements (Smit 1999; International Human Genome Sequencing Consortium 2001). The wealth of human genomic information now allows comprehensive explorations into the evolutionary history and genomic distribution patterns of transposable elements with a view to increasing our understanding of the forces that have shaped our genome and its mobile inhabitants. The retroelements present in the human genome are divided in two major types, the non-LTR and LTR retroelements (International Human Genome Sequencing Consortium 2001). The non-LTR retroelements are represented by the autonomous LI and L2 elements (LINE repeats) and the non-autonomous Alu and MIR (SINE) repeats and have been extensively studied (Smit 1999; International Human Genome Sequencing Consortium 2001; Ostertag and Kazazian 2001; Batzer and Deininger 2002) but appreciation of the heterogeneous collection of LTR retroelements is more limited. These sequences make up 8% of the human genome (International Human Genome Sequencing Consortium 2001) and include defective endogenous retroviruses (ERVs) (Wilkinson et al. 1994; Sverdlov 2000; Tristem 2000), related solitary LTRs, and sequences with LTR-like features for which no homologous proviral structure has been found. Over 200 families of LTR retroelements are defined in Repbase (Jurka 2000) but they can be grouped into six broad superfamilies (see Methods). While some of the LTR retroelement families, particularly members of class I and II ERVs, presumably entered the primate germline as infectious retroviruses and then amplified via retrotransposition (Wilkinson et al. 1994; Sverdlov 2000; Tristem 2000), other LTR families likely represent ancient retrotransposons that amplified at different stages during mammalian evolution (Smit 1993). The vast majority of human retroelements were actively transposing at various stages prior to and during the radiation of mammals and are now deeply fixed in the 35 primate lineage. Essentially only the youngest subtypes of Alu (Batzer and Deininger 2002) and L I elements (Ostertag and Kazazian 2001) are still actively retrotransposing in humans. Some ERVs belonging to the Class II H E R V - K family are human-specific (Medstrand and Mager 1998) and a few are polymorphic (Turner et al. 2001) but no current activity of human ERVs has been documented. Here we show that genomic densities of human retroelements vary with distance from genes and that their distributions with respect to surrounding GC content also shift as a function of their age. 2.2 Methods 2.2.1 Description of retroelements Human retroelements are classified into two major classes: non-LTR and LTR retroelements. The former contain the LINEs, represented by the L I and L2 elements, whereas the Alu and MIR elements belong to SINEs. For this analysis LTR retroelements were divided into the following six groups (Smit 1999; Jurka 2000; International Human Genome Sequencing Consortium 2001; Mager and Medstrand 2003): class I ERVs, which are similar to type C or gamma retroviruses such as murine leukemia virus; class II ERVs, which are similar to type B or beta retroviruses like mouse mammary tumor virus; class III ERVs (also called ERV-L) , which have limited similarity to spuma retroviruses; MER4 elements, which are non-autonomous class I related ERVs; and MST (named for a common restriction enzyme site Mstll) and M L T (mammalian LTR transposon) elements, which are both part of the large non-autonomous Mammalian apparent LTR Retrotransposon (MaLR) superfamily. Solitary LTRs outnumber LTR elements with internal sequences by approximately 10 fold. 36 2.2.2 Data sources Genomic sequence and annotated gene data for all figures were derived from the August 6, 2001 draft human genome assembly at Retroelement locations derived from RepeatMasker (, GC-content calculated in non-overlapping windows of 20-kb, sequence gap data, and known gene data from the Reference Sequence database were all downloaded from this site. After compilation, data points were included in graphs only i f supported by more than 100 retroelements. Element count was calculated to reflect as nearly as possible the number of individual integrations of the element. That is, nearby repeat segments (within 20 kb of each other) having the same family name and RepeatMasker alignment parameters (alignment score, substitution and gap levels) were combined and treated as a single element. Subfamily assignments and divergence values were taken directly from RepeatMasker output files. Internal sequences of LTR elements were excluded from the analysis. Data was further conditionally discarded in figures where retroelement divergence is used as a measure of age. In some cases where element length was short (below 150 bp), it was noted that RepeatMasker assigned an artificially low divergence value due to the alignment method used in finding repeats. This was a particular problem for the old MIR and L2 sequences. An attempt was therefore made to ensure that relative divergence indeed represented age by plotting element length versus assigned divergence values. Since repeats in general grow shorter as they age (e.g. see Figure 2.5), retroelement divergence cohorts were considered anomalous and discarded i f they did not follow this trend. 2.2.3 Density analysis The retroelement data were compiled by repeat superfamily, divergence from consensus, 37 and surrounding genomic GC content. The density function in Figures 2.1, 2.4 and 2.6 was calculated as follows: the fraction of the retroelement base pairs in a given GC bin divided by the fraction of the genome in that GC bin. Thus, it affords a measure of preference of a particular age class for different GC contents. When an age class of an element had a significant presence in only some of the GC bins, the effective genome size for that age class was calculated from the sizes of only those GC bins. Thus for the Figure 2.6 genomic data, the 'whole genome' is that fraction of the genome with GC content less than 46%. In Figure 2.2, the bin considered was an individual chromosome. With these considerations in mind, the calculations of density are identical. For Figure 2.2 (retroelement density versus GC content on each chromosome), correlation coefficients (r) and level of significance (p-values) were calculated for each data set. The graphs of chromosomal retroelement density as a function of gene density are not shown, but are almost identical because of the highly significant correlation between GC content and gene density (International Human Genome Sequencing Consortium 2001). For Figure 2.3, a script divided the chromosomes into eleven segment types or bins: within the transcript start and end positions of known (annotated) genes and 0-5, 5-10, 10-20, 20-30, and >30 kb upstream and downstream of genes. The majority of the genome was located either within genes (22% of the total) or at distances greater than 30 kb from genes (63% of the total). In each segment, the script determined the base pair contribution of each retroelement type and noted the orientation of the element with respect to the nearest gene. The GC content of each segment was calculated and then the density data from Figure 2.1 was used to predict the base pair contribution by each retroelement type in the segment. Predictions done within genes or at distances >30 kb 38 from genes were compiled from predictions made from 10 kb sub-segments. Half of the predicted retroelement base pairs were assumed to be in the sense orientation and half in antisense. Finally, the observed base pairs in each bin were divided by the cumulative predicted base pairs for each retroelement type. P values shown in Tables 2.1, 2.2, and 2.3 and variability of the data in Figures 2.3, 2.4 and 2.6 were calculated as follows. The sequence segments comprising the whole genome were divided up into four 'subgenomes' of equal composition. The retroelement distributions were calculated in each subgenome, and the means and standard deviations of retroelement distributions were calculated. After appropriate normalization, the significance (p-value) of the difference between different retroelement distributions was tested by the one-tailed unpaired t-test. 2.3 Results and Discussion 2.3.1 Distributions of retroelements in different GC domains To begin our analysis, we measured the density of various retroelements with respect to GC content in 20-kb windows across the human genome sequence. As reported previously (Smit 1999; International Human Genome Sequencing Consortium 2001), LI elements are predominantly found in the AT-rich regions, L2 elements are more uniformly distributed whereas Alu and MIR repeats reside in the higher GC fractions of the genome (Figure 2.1 A) in comparison to the entire genome which has an average GC content of 40% (International Human Genome Sequencing Consortium 2001). For the different LTR superfamilies, an uneven distribution in GC occupancy is also observed. The relatively young Class I ERVs and the non-autonomous MER4 sequences, which 39 may have been propagated by Class I elements, have very similar broad distributions that peak in regions of medium GC. Class II ERVs, which include the youngest known HERVs (Medstrand and Mager 1998; Turner et al. 2001), have a distribution more skewed toward higher GC regions (Figure 2. IB). Distributions of the older Class III ERVs and their distantly related M L T and MST elements are generally biased toward low GC regions, except for M L T elements which are spread more uniformly (Figure 2.1C). 40 A 2 I | 0 H 1 1 1 1 1 ' 1 1 1 1 1 1 O <34 36-38 40-42 44-46 48-50 52-54 >54 c c 0 -I 1 1 1 1 1 1 1 1 1 1 1 1 _ <34 36-38 40-42 44-46 48-50 52-54 >54 O g - | , , , , , , , , 1 I 1 1 <34 36-38 40-42 44-46 48-50 52-54 >54 Genomic GC (%) A B C - • -Alu - « - Class I ERV -x- Class III ERV -o-L1 -*— Class I  ERV —A— MLT —B— MIR -*— MER4 -9- MST - • - L 2 Figure 2.1 Density of retroelements in different GC fractions in the human genome, calculated over 20-kb windows across the genome sequence. Panels A to C show the density of various retroelement classes and those represented in each panel are indicated in the box below the graphs. The bins from left to right correspond to an increasing 2% GC fraction. 41 To determine if retroelement densities on each chromosome agree with overall densities shown in Figure 2.1, we plotted densities against estimated gene (data not shown) or average G C content of each chromosome (Figure 2.2). As expected, the two distribution profiles are almost identical because of the strong correlation between GC content and gene density (International Human Genome Sequencing Consortium 2001). The density of Alu elements increases as a strict function of increasing GC content and MIR elements also generally follow this trend (Figure 2.2A, C). In contrast, there is generally a negative or no correlation between the density of L I , L2 or L T R elements and gene density or GC content (Figure 2.2). The Class II ERVs and the M L T elements show little, if any, bias for GC-poor chromosomes, while the L I , Class I, III and MST groups are overrepresented on these chromosomes. Class I-II elements are dramatically over represented on chromosome Y, as noted before (Kjellman et al. 1995; Smit 1999; International Human Genome Sequencing Consortium 2001), and also somewhat on 19. Abundance of the youngest ERVs on chromosome Y may be due to recombination isolation and absence of major recent rearrangements on much of this chromosome (Graves 1995; Lahn et al. 2001), and since chromosome 19 is much more gene-dense than the other chromosomes (International Human Genome Sequencing Consortium 2001), one possible explanation for the over-representation of the same ERVs on this autosome is that these elements had an initial integration preference for regions near genes or gene-related features such as CpG islands. We also noted an under representation on Y of the old L2, MIR and M L T retroelements which is consistent with major rearrangements and deletions of Y during mammalian evolution (Lahn et al. 2001). Similar trends are observed for MER4 distributions and their autonomous class I counterparts (over representation on Y and 19), and for the non-autonomous MaLR 42 (MLT and MST) elements and their apparent autonomous class III ERVs (over representation on 21). Alu , L I , MER4, class I and II E R V sequences represent the younger elements which have actively amplified during the last 40 M Y R of primate evolution, whereas other element types were already inactivated for transposition by this time (International Human Genome Sequencing Consortium 2001). A l l younger retroelements except Alu sequences are over represented on Y . Even though some of the LTR superfamilies show a stronger negative correlation than others, the distribution profiles demonstrate that various retroelement families cluster preferentially in different genomic landscapes and are in agreement with the general trends observed in Figure 2.1. 43 3 , A Alu p<1 e-11 2.5 -2 -1.5 -1 0.5 H 0 1.5 1 0.5 2 -,B L1 p<1e-11 <> X O Y i 1 1 1 1 1 1 1 1 1 1 1 L 36 38 40 42 44 46 48 36 38 40 42 44 46 48 2 ,C MIR p<1e-5 1.5 H E 1 H 9l 0.5 D) •B o 190 O Y i 2 -I 1.5 -1 0.5 0 D L2 p=0.46 • O Y 36 38 40 42 44 46 48 g. 2 ^ I. 1.5 H i 1 E 0.5 a o MLT p=0.012 021 O Y O20 • 1.5 1 0.5 — i 1 1 1 1 1 36 38 40 42 44 46 48 2 -jF MST p<1e-8 0 21 V * s * ^ «. - I 1 r -C o r 2 °- 1 0.5 H 0 36 38 40 42 44 46 48 36 38 40 42 44 46 48 G MER4 p=0.0015 021 19 O 1.5 1 0.5 0 2 -|H Class III ERV p<1e-9 • 21 O Y O20 .... • 36 38 40 42 44 46 48 36 38 40 42 44 46 48 4 n l Class I ERV p<1e-8 3 • ° Y 2 1 0 # ^ r 5 J Class II ERV p=0.26 4- ° Y 3 • 2 • 1 -0 • 19" v«4** ™r 1 1 r -1 1 1 1 1 1 36 38 40 42 44 46 48 36 38 40 42 44 46 48 G C (%) Figure 2.2 Density of retroelements as a function of average GC content of each human chromosome. The line connecting solid diamonds indicates the general correlation trend between retroelement and GC content of individual chromosomes. The level of significance (p-values) of the correlation for each data set is indicated. Open diamonds were excluded from the correlation analysis and indicate over or under representation of retroelement density on a particular chromosome. Chromosomes 20, 21 and 22 were excluded from the Class II graph (panel J) due to having less than 100 supporting elements. 44 2.3.2 Arrangements of retroelements with respect to genes Given the results in Figures 2.1 and 2.2, we looked in more detail at the distribution of retroelements by locating all elements in the human genome relative to annotated genes. While it is reasonable to assume that locations with respect to genes affect retroelement dispersal and fixation patterns, the aim of this analysis was to obtain a measure of this effect. Our strategy was to determine how closely retroelement densities with respect to genes could be predicted based on the surrounding GC content. D N A regions located upstream of each gene's transcriptional start site and downstream of the polyadenylation site were divided into segments of various size fractions (see Methods) and the density of each retroelement class in either transcriptional orientation with respect to the gene was determined. Regions within the boundaries of a gene, including the introns, were assigned a single segment. The local GC content of each segment was also calculated and used to determine an expected retroelement density based on the whole genome distributions indicated in Figure 2.1 (see Methods) and the results shown in Figure 2.3. To obtain estimates of the variation associated with this type of analysis, we divided the genome into four 'subgenomes' as detailed in Methods and performed the analysis independently for each. The points in the graphs represent the mean and standard deviation derived from values obtained for each subgenome. 45 ^ gene <5 10-20 >30 *30 10-20 <5 gene gene <5 10-20 >30 >30 10-20 <5gene 5 E MLT F MST a 1.5i 1 1.5] 12 1 CL - 0.5 T> 81 o 5 gene <S 10-20 >30 >30 10-20 <5 gene gene <5 10-20 >30 >30 10-20 <S gene T a •a MER4 Class lit ERV 2 1.5 1 0.5 1.5 0.5 gene <5 10-20 >30 >30 10-20 <5 gene gene <5 10-20 >30 >30 10-20 <5gene Class I ERV J Class II ERV gene<5 10-20 >30 >30 10-20 <5 gene gene <5 10-20 >30 >30 10-20 <5gene J|Downstream (kb) Upstream ^Downstream (kb) Upstream -1 V sense — • — A n t i s e n s e Figure 2.3 Ratios of observed to predicted retroelement densities with respect to genes in the human genome. The points above 'gene' and '<5' of each graph indicate the density in gene regions, and in the first 5 kb either 5' or 3' of genes. The other bins are 5-10,10-20, 20-30, and >30 kb either upstream or downstream of genes. Open symbols and dashed lines indicate elements in the same or sense orientation with respect to the nearest gene and solid symbols and lines indicate elements in the reverse direction. Standard deviation error bars, which are too small to see in some cases, were determined as described in Methods. Solid boxes below the graphs represent gene regions and the lines indicate the distance bins of the intergenic regions. It should be noted that the vast majority of retroelements within genes are located in introns. 46 Dividing the genome based on proximity to genes revealed several intriguing patterns. First, densities of the relatively old MIR and L2 elements in intergenic regions generally conform to that predicted from the GC content of each region. That is, the ratio of observed to expected density is close to one (Figure 2.3C, D). Second, for the SINE (Alu and MIR) elements, densities within genes are close to that predicted or are overrepresented based on average GC content of gene regions (Figure 2.3A, C). In contrast, LI elements and all six LTR classes, particularly those in the same transcriptional direction, are underrepresented within genes (Figure 2.3B, E-J). LI sequences and the older M L T , MST and Class III elements are also underrepresented in the 0-5 kb regions both upstream and downstream of genes, while the younger class I and MER4 elements are underrepresented in the downstream region only. The higher tendency for L T R elements and L i s within genes to be oriented in the antisense direction has been noted previously (Smit 1999) and likely reflects lower fixation rates resulting from interference by retroelement regulatory motifs, such as polyadenylation signals, when genes and elements are located in the same transcriptional direction. However, this is the first study to demonstrate lower densities of LTR and L I elements within genes relative to that predicted based on the surrounding GC content. In addition, the fact that an orientation bias for some elements extends to significant distances away from genes has not been reported previously. Moreover, our analysis indicates that the densities of most LTR elements and L i s are highest in regions furthest from genes. These patterns suggest that L I and L T R elements are excluded from genes and nearby regions by selection. Interestingly, the density distribution of Alu elements with respect to genes is opposite to that observed for L I and most LTR elements in that the density is lowest in 47 regions most distant from genes and they are overrepresented (as predicted by GC content) in regions within and near genes. It is also noteworthy that densities of the relatively young LTR class II elements peak in the region 5-20 kb 5' or 3' of genes and, indeed, are overrepresented in these areas compared to the expected densities based on regional GC content (Figure 2.3J). Such a pattern may reflect a preference for this class of elements to integrate near genes. The statistical significance of these results is shown in Table 2.1 which lists the resulting p-values for three sets of comparisons. The top part of the table compares the sense versus antisense distributions and confirms the significance of the orientation biases discussed above. MIR elements are the only group to show no significant orientation bias. In contrast, an orientation bias extends up to 20 kb 5' of genes for M L T and MST elements. The bottom two panels in Table 2.1 compare densities of retroelements in each orientation at each intergenic location to the densities of retroelements in regions most distant (>30 kb) from genes. These latter comparisons illustrate that the retroelement density differences plotted relative to gene location are highly significant. For example, the densities of Alu sequences at all locations are highly significantly different from their density in regions >30 kb from genes. 48 Table 2.1 Significance (p-values) of retroelement locations with respect to genes Sense vs. antisense in 0-5 dnst" 5-10dnst 10-20 dnst 20-30 dnst >30 dnst >30 upstc 20-30 upst 10-20 upst 5-10 upst 0-5 upst in Class I Class II 0.25 0.16 0.42 0.053 "~ 0.043! 0 17 6.0E-05 O^TOOI] 0.001 4.9E-05 , 0 096f3pp70]03] 2.9E-05 SJE-OS^^E-Oe 3.6E-04 1.6Er04 Antisense vs. >30 kb from genes Alu L1 MIR L2 MLT MST MER4 Class III Class I Class II in 8.9E-06 " .0.015 0.13 ,. 0.007 ' 0.003 1.2E-04 0.001 6.9E-05 4.3E-05 0.02 0-5 dnst 9:9E-07 2 3E-06 ""0T006 0.1 1.3E-04'/ 1.0E-04 0.005 0.012 0.015 0.27 5-10 dnst 7.1E-07 0.45 0.009 0.29 ' ' 0.006 0.018 0.08 0.12 0.42 ~^ 8E~5"~ 10-20 dnst 4.9E-07, 0.058 0.003 0.49 0.026 0.097 0.07 "07602~ 07005 6.006 20-30 dnst 1.1E-06 0.002 0.074 0.5 0 011 0 03' 0.18 0.41 • 0.005 20-30 upst 4.2E-07 0.38 0.2 0.27 0.06 0.007 0.033 ' o:or 07013 0.17 10-20 upst 1.5E-07 * list*-0.38 70.01~r~T0.0T2" """""070~45 0.064 0.061 0.054 0.46 '07014 5-10 upst 2.1E-07, "0.00$ 0.083 0.001 0.38 0 004 0.022 > 0.029' A i r •* -t <rf """07028 ' 0^.022 0-5 upst 3.0E-07 .3.0E-06 0.34 7.7E-05 ~"274E"05 •4.8E-04 0.033 1.2E-06I 0.06 . 0.016 in 8.9E-06 /" 0.015 t 1 ^ 1*1 g 0.13 0.007 0.003 ' 1.2E-04 0.001 6.9E-05 473E-05 ; 0.02 Sense vs. >30 kb from genes Alu L1 MIR L2 MLT MST MER4 Class I Class I Class I in 0-5 dnst 5-10 dnst 10-20 dnst 20-30 dnst 20-30 upst 10-20 upst 5-10 upst 0-5 upst in 1-.7.E-04 8.6E-07 0 069 6.9E-06 9.3E-05 1.0E-06 *> fftp , A , ,,u,. 9.0E-07J 0.45 2.9E706 "~1>7007 0.14j, "07002 0.096 0.4 0.053 .3.9E-06 1.8E-07J ./1.4E-07 '4.7E-07~"""T07q2' 6.8E-07 6.8E-07 f Ell lift $ ft tV 1.7E-04 8.6E-07 0.003 0.003 .0.011 0.36 0.066 0 41f 0.13 0.069 0.12^  0.39 0.24 0.24 0.24 ~070"I2" 0.012 4:4E-07,, 2 5E-06 0.003 0.14 0.15 0.28 ~~~"070Y2 0.015 ' 0.026 2.1E-05 4.4E-07 2.2E-06 2.3E-05 ' 0.001 0.019! '1.3E-07 1.0E-05 0.22 7""07002 * 0.003I 4.6E-04 1 3E-06 2.2E-06 0.391 "07034 1 0.03 1.6E-07, 1.5E-07' 1.3E-05 l!9E-04 2.0E-06 0.003 0.02 0.44 0.23 0.14 ~~070"17 '1.3E-07 0.068 07002| 0.002 0.045, >8:3E-06l 0.48 0.18 0.078 0.073 0.3 0.055 ~0700'5 0.002 0.4 0704™ 0.041; 0.002 0.043 0.33 0.48 1.6E-07~1.5E-07 1.3E-05 Shaded regions are significant (p < 0.05) awithin a gene bdnst: kb downstream of the nearest gene cupst: kb upstream of the nearest gene 49 2.3.3 Shifting retroelement distributions with age It is apparent that the retroelement distributions in genes and intergenic regions (Figure 2.3) do not fully conform to the genome-wide distribution patterns of elements observed in Figures 2.1 and 2.2. Furthermore, for Alu repeats, it has been reported previously that young elements (< 1 Myr) have a preference for AT-rich regions whereas older Alus show an increasing density in GC-rich D N A (Smit 1999; International Human Genome Sequencing Consortium 2001) (see Figure 2.4A) and hypotheses to explain this phenomenon have been proposed (Schmid 1998; Brookfield 2001; International Human Genome Sequencing Consortium 2001; Pavlicek et al. 2001)(see Section 1.2.4). Transposition into AT-rich regions might be expected to lead to accumulation of TEs in this gene poor part of the genome (e.g. the heterochromatin) where recombination is strongly reduced and element interference with genes is less pronounced. However, the observed density differences of the youngest Alu elements (present in A T rich regions) as opposed to older elements (in GC rich regions) do not follow this expectation. A possible explanation for the age-related Alu density differences is that these retroelements are removed preferentially from their initial integration sites in the A T rich regions of the genome prior to fixation. However, because there is a gradual density increase of Alu elements by age in the GC rich fraction, it is possible that already fixed elements are gradually lost from the A T rich region while they are maintained in GC rich regions. 50 • <34 36-38 40-42 44-46 48-50 52-54>54 <34 36-38 40-42 44-46 48-50 52-54>54 o 4—i—i—i—i—i—i—i—i—i—i—i—i o i—i—i—i—i—i—i—i—•— 1— 1— 1 1 <34 36-38 40-42 44-46 48-50 52-54>54 <34 36-38 40-42 44-46 48-50 52-54 >54 I Class I ERV _ J Class II ERV 2 1 2 I 0 -I—•—i—i—i—i—i—i—i—i—i—i—i 0 •—i—•—i—•—i—i—•—•—•—i—'—> <34 36-38 40-42 44-46 48-50 52-54>54 <34 36-38 40-42 44-46 48-50 52-54 >54 Genomic OC (%) -B-0-1 1-5 -• -0-5 -B-5-10 —_- 10-15 - K - 15-20 —3K— 20-25 25-30 —1—30-35 — « - 35-40 — - 40+ Figure 2.4 Retroelement densities of different divergence classes in various GC fractions of the human genome. The density distribution of each retroelement divergence cohort was plotted in GC bins as indicated in the legend to Figure 2.1. The divergence classes are indicated in % divergence from the consensus sequence below the graphs. Data points missing in traces are due to GC bins containing less than 100 elements. Standard deviations were calculated (see Methods) but are not shown in the interest of clarity. 51 To investigate if other retroelements also change their genomic distribution with age, we determined the distribution patterns of LTR elements, SINEs and LINEs of different ages as a function of GC content (Figure 2.4). As discussed above, it is apparent that the youngest Alu elements (0-1% divergent), many of which are polymorphic insertions (Carroll et al. 2001; Batzer and Deininger 2002), are distributed differently than the next youngest (fixed) Alus of the 1-5% divergence group and that the densities of the next two Alu age cohorts (5-15% divergent) are skewed even further to GC-rich regions (Figure 2.4A). Notably, this figure also reveals that the oldest Alu repeats are less prevalent in GC-rich domains and, indeed, have a density distribution closer to that of the youngest age class. This density pattern of the oldest Alu elements was not evident in a similar analysis reported previously (International Human Genome Sequencing Consortium 2001). In that study, Alu elements were divided by subfamily instead of divergence and the density of the oldest subfamily, AluJ, was still highly skewed to GC rich regions. However, the AluJ subfamily was considered as a single large cohort, the members of which have divergences ranging from less than 10% to greater than 25%>. When the more divergent AluJ members of 15-20%) and 20-25%) divergence are separated into their own groups, their densities are essentially identical to the patterns presented in Figure 2.4A (data not shown). Thus, the different methods for separating Alu elements accounts for the differences between our analysis and that in the genome consortium study. Results of similar analyses conducted for the other retroelements reveal some provocative trends. As noted before (Smit 1999) and as shown in Figure 2.4B, young LI elements are preferentially found in the AT-rich fraction in the genome and older 52 elements tend to be found in the most AT-dense part of the genome. Analysis of the ancient L2 and MIR repeats was hampered by the short average length of most elements which prevented an accurate determination of their divergence from a consensus sequence (age) (see Methods for details). However, for the two divergence classes that could be reliably determined, the oldest L2 and MIR sequences also show an increased density in the less GC rich sections of the genome compared to their younger counterparts (Figure 2.4C, D). For most of the LTR elements, we observe a trend similar to that seen for the L2 and MIR sequences. For elements belonging to the M L T , MST, MER4, Class I and III ERV groups, densities of the youngest members of these superfamilies peak in regions of higher GC compared to their older relatives (Figure 2.4E-I). That is, the highest concentrations of these elements appear to gradually shift to regions of lower GC with increasing age. This tendency is not evident for the Class II ERVs (Figure 2.4J). Potential explanations for this trend will be discussed below. To determine if the shifting patterns observed in Figure 4 are statistically significant, we again divided the genome into four subgenomes and repeated the analysis for each of these. Each point in the graphs could then be assigned a mean and standard deviation based on values obtained for each subgenome. The t-test was used to determine if the density distribution of a particular age cohort was significantly different when compared to the next oldest cohort. Table 2.2 lists the p values resulting from this analysis. For all retroelements except the Class II ERVs, the majority of the density points are significantly different (p < 0.05) for at least one comparison between adjoining age cohorts. Indeed, for the most numerous elements, Alu and L I , almost all comparisons are statistically significant. If the youngest and oldest age cohorts of each 53 superfamily are compared, all except the Class II ERVs are highly significant (data not shown). 54 Table 2.2 Significance (p-values) of distributional differences between divergence cohorts B0-1: 1-5 1-5: 5-10 Alu 5-10: 10-15 10-15: 15-20 15-20: 20-25 20-25: 25-30 0-5: 5-10 5-10: 10-15 10-15: 15-20 L1 15-20: 20-25 20-25: 25-30 25-30: 30-35 30-35:1 35-40 <34a 34-36 36-38 38-40 40-42 42-44 44-46 46-48 48-50 50-52 52-54 >54 <34 34-36 36-38 38-40 40-42 42-44 44-46 46-48 48-50 50-52 52-54 >54 <34 34-36 36-38 38-40 40-42 42-44 44-46 46-48 48-50 50-52 52-54 >54 MIR 30-35: 35-40 0.23 1.0*00,1 . • • • - l 0:036 L2 30-35: 35-40 35-40: 40+ 0.24 0.05 0.20 0.48 0.07 Class I 15-20: 20-25 20-25: 25-30 25-30: 30-35 MLT 15-20: 20-25: 20-25 25-30 25-30: 30-35 0.22 MST 10-15: 15-20 15-20: 20-25 Class I 5-10: 10-15 10-15: 15-20 15-20: 20-25 20-25: 25-30 a G C content (%); Divergence cohorts compared MER4 10-15: 15-20: 20-25: 15-20 20-25 25-30 Class II 5-10: 10-15 10-15 15: -20 0.32 0.20 0.21 0.07 0.46 0.08 loiaMS o.i8 0 18[@t0l00'1i 55 One qualification regarding this data concerns the method used to identify retroelements of different ages. Elements were classified as belonging to divergence cohorts based on percent substitution from their consensus sequence (Jurka 2000). The consensus sequence corresponds to the approximate sequence at the time of integration in the genome, where retroelements in higher divergence cohorts indicate an older time of integration relative to the retroelements of lower divergence values (Li and Graur 1991; Shen et al. 1991; Smit et al. 1995; International Human Genome Sequencing Consortium 2001). Therefore, the validity of this method is highly dependent on having accurate consensus sequences for all subfamilies. It is quite possible and even likely that some elements have been assigned an incorrect age due to extreme heterogeneity of some of the retroelement classes, particularly among the LTR groups. However, i f this was a major problem, one would not expect to observe a consistent shift in density in one direction - namely toward lower GC regions with increasing divergence. 2.3.4 Length differences do not account for the shifting patterns To investigate potential mechanisms that may underlie the age related distribution differences, we used two different methods to try to determine i f differential rates of retroelement deletions in different genomic GC regions account for the shifting patterns observed in Figure 2.4. First, we examined the relative length of elements in different GC fractions. The results of this analysis indicated that retroelements gradually become shorter as they age, presumably due to small deletions or loss of recognition of diverged segments by RepeatMasker, but the shortening is largely independent of the surrounding GC content (data not shown). The two exceptions to this general observation are represented by LI elements and older Alu sequences (Figure 2.5). The average length of 56 younger LI elements (<10% divergence) peaks in the 38-42% GC fractions which might explain the abundance of LI base pairs in this region (Figure 2.4B). In the case of Alu elements in the 20-30%) divergence cohorts, there is a slight decrease in apparent length with increasing GC content (Figure 2.5B) but this is not enough to account for the density pattern of this age group (Figure 2.4A). In addition, the small degree of shortening as measured here does not explain the rapid enrichment of younger Alu elements in higher GC fractions. Figure 2.5 Length distribution of retroelements with respect to surrounding GC content. Retroelements of each group were classified as belonging to divergence cohorts as described in the text. The average length in base pairs (bp) of each retroelement divergence cohort contained within each GC bin (see legend to Figure 2.1) is shown for LI and Alu elements (panels A and B). GC bins containing less than 100 elements were excluded from the graphs. 57 2.3.5 Delay of Alu density changes on the Y chromosome As another way of investigating the change in distribution of younger Alus toward GC-rich regions, we analyzed Alu density patterns on the Y chromosome, much of which does not recombine (Graves 1995), and detected a major difference on this chromosome compared to the whole genome (Figure 2.6). Alu elements on chromosome Y less than 5% divergent are not numerous enough to include in this analysis. However, the density pattern of Alus in the 5-10% divergence class is strikingly opposite to that observed in the whole genome in that they are much more prevalent in AT-rich regions compared to GC-rich regions (Figure 2.6C). The distributions of older Alu elements (>10%> divergent from the consensus) with respect to GC content are consistent with the patterns seen in the entire genome (Figure 2.6D-F). Table 2.3 shows the p values resulting from this analysis. This finding suggests that the density shift of Alus from AT-rich to GC-rich regions during evolution was significantly delayed on the Y chromosome and, therefore, that the ability to recombine with a homologous chromosome greatly facilitated this shift. Table 2.3 Significance (p-values) of distributional difference between Alus on the Y chromosome versus the whole genome "5-10 10-15 15-20 20-25 34-36" |v> 0'P012^ « 0.0231 0.13! :0.022 40-42 ^bi039 0.41 0.27 42-44 0.10 0.24 0.34 44-46 0.11 0.08 58 1.5 O 0 c 0.5H i 0-1% diverged 2 1.5 0.5 T I B 1-5% diverged o 2 2 U c B) 1 £ 0.5 o o c S 2 o re •i 1 0.5 <34 C 36-38 40-42 44-46 <34 36-38 40-42 44-46 5-10% diverged 2.5 2 1.51 1 0.5 " r " " 1 " " T " " " " i " — t D 10-15% diverged I I I <34 E f-36-38 40-42 44-46 <34 36-38 40-42 44-46 15-20% diverged 2 ] F 20-25% diverged 1.5 0.51 —1 1 1 1 <34 36-38 40-42 44-45 <34 36-38 40-42 44-46 Genomic GC (%) Figure 2.6 Density of Alu divergence cohorts in different GC fractions on chromosome Y compared to the whole genome. Solid lines indicate Alu elements on chromosome Y whereas dashed lines represent the Alu density in the whole genome. Parts A to F indicate the density of a specific divergence class which is indicated on the top of each panel. There were insufficient numbers of Alu elements on the Y chromosome in the first two divergence cohorts to be plotted in panels A and B. The density distribution of each Alu divergence class is plotted against the local 20-kb genome GC content. Standard deviations were calculated as described in Methods. 2.3.6 Potential explanations for Alu distribution patterns The density patterns of A l u elements do not conform to trends observed for other retroelements. These elements integrate into the AT- r i ch part but accumulate in GC-r ich D N A (International Human Genome Sequencing Consortium 2001) (Figure 2.4A) and at least three hypotheses have been proposed to account for this phenomenon. One proposed explanation is that the GC-r ich A l u elements are more stable in regions where the surrounding G C content is similar (Pavlicek et al. 2001). However, we have observed that partial deletions or apparent shortening of various A l u age groups are uniformly 59 distributed irrelevant of GC occupancy (Figure 2.5B). This finding does not seem to support such a hypothesis although it is possible that the tendency of retroelements to remain in regions of matching GC content does play some role. A second hypothesis proposes that Alu elements are selectively retained in GC-rich regions because having these elements close to genes is of functional benefit (Britten 1997; Kidwell and Lisch 1997; Schmid 1998). Figure 2.3 A shows that the Alu density near genes is higher than predicted based on GC content. That is, the tendency of Alu elements to be located near genes is not fully explained by the general GC-richness associated with coding regions and such a pattern may therefore reflect a functional role for these elements. However, other observations appear discordant with this view. For example, it is known that the developmentally critical HoxD gene cluster is almost devoid of retroelements (International Human Genome Sequencing Consortium 2001). A recent study has also found that SINEs (Alu and MIR elements) are less frequently associated with imprinted than non-imprinted genomic regions (Greally 2002). Certain classes of genes may therefore need to exclude such sequences from their environment to ensure proper function or regulation. A third hypothesis proposes that the maintenance of Alus in GC rich regions may be due to the adverse effects that deletions and unequal recombinations could have in gene-rich regions (Brookfield 2001). Indeed, due to the vast numbers of Alu elements in the genome, it is likely that specific recombinational mechanisms have been a major force in shaping the distribution of Alus in the genome. It has recently been demonstrated that the efficiency of Alu-Alu recombination in yeast increases as a pair of elements are placed closer together (Lobachev et al. 2000). Such closely spaced Alu pairs are found only occasionally in the human genome (Lobachev et al. 2000; Stenger et al. 60 2001) , possibly because of clearance of these elements through the mechanism of inverted repeat (IR)-mediated recombination (Leach 1994). Alu elements seem quite promiscuous for recombination because two elements up to 20% divergent are still able to recombine efficiently (Lobachev et al. 2000). Furthermore, there are many examples of Alu-mediated recombination resulting in mutations in humans (Batzer and Deininger 2002) . These findings suggest a possible explanation for the changing Alu distribution profiles shown in Figure 2.4A and their enrichment near genes. Considering the high number of genomic Alu elements and the fact that they preferentially target AT-rich regions, these domains must have suffered a massive build up of Alu integrations. Such accumulation likely resulted in increased recombination as the occurrence of closely spaced, highly related Alus increased which could have led to loss of both newly integrated and fixed Alu elements in the A T rich fraction of the genome. In regions close to genes, it is possible that Alu-Alu recombination events are less likely to be allowed or become fixed because of an increased chance of simultaneously removing gene regulatory domains (Brookfield 2001). This could help explain the over-representation of Alu elements near genes without invoking a functional role. The fact that we observe no increased density in GC- or gene-rich regions for the oldest Alus could be explained by the fact that Alus in these age cohorts are much less numerous and therefore would have been less subject to loss via recombination in AT-rich regions. Alu elements of 20-30% divergence are present in only -25,000 copies whereas younger Alus in the 5-10, 10-15 and 15-20% divergence classes are present in -300,000, 480,000 and 210,000 copies respectively. Furthermore, due to their higher divergence values, the oldest Alus would also have been less able to recombine with their younger, more numerous relatives when the latter populated the genome. 61 Differences in recombination are likely also responsible for the fact that Alu elements are not over represented on chromosome Y as are other younger retroelements such as Class I and II ERVs (International Human Genome Sequencing Consortium 2001) (Figure 2.2). This finding suggests that Alus are lost more readily than the LTR elements. However, loss of Alu elements on the Y appears delayed compared to on the autosomes (Figure 2.6), likely because only intrachromosomal/IR recombination can operate on most of the Y. IR recombination seems to work more efficiently when two elements are closely located (Lobachev et al. 2000) and it is likely that this is true also for intrachromosomal recombination in general. Thus we postulate that LTR elements are removed less efficiently than Alu elements due to their much lower copy number and, therefore, larger average inter-element distance. 2.4 Concluding remarks One view of transposable elements considers them to be selfish D N A of no use to the host (Doolittle and Sapienza 1980; Orgel and Crick 1980; Yoder et al. 1997), while others hypothesize that their fixation reflects functional interactions with the host (McDonald 1995; Brosius 1999). Our data support the idea that retroelements have a general negative impact on the host because of a gradual accumulation of most retroelement superfamilies in the A T rich fraction and on the Y chromosome (which is predicted to occur according to the selfish D N A hypothesis) (Charlesworth et al. 1997). However, these findings also support a concept in which retroelements gradually are cleared (or maintained) from the host genome, a relationship that seems dependent on the age of their association. (Di Franco et al. 1997; Junakovic et al. 1998; Torti et al. 2000; Kidwell and Lisch 2001). The fact that densities of old MIR and L2 retroelements near genes are close to that predicted by average GC content suggests a relatively benign 62 relationship between these retroelements and genes. In contrast, retroviral elements may have interfered more often with gene function due to initial integration site preference into gene rich regions. The density pattern of the relatively young class II ERVs (Figure 2.3 J) supports this suggestion. Of those LTR elements which have been fixed in the population (i.e. almost all those in humans), our analyses have revealed that the highest densities of the older elements gradually shift with age to AT-rich or gene-poor DNA. Furthermore, we have shown that all types of LTR retroelements are significantly underrepresented within genes. Since LTRs carry transcriptional regulatory signals very similar to those in cellular genes (Majors 1990), it seems reasonable that insertion of an LTR close to or within a gene would frequently be disadvantageous unless it is efficiently silenced by methylation or other mechanisms (Yoder et al. 1997; Whitelaw and Martin 2001). Such insertions with a marked negative impact will be selected against with no chance to spread to fixation. However, it is known that a mutation with a selective disadvantage can still be fixed through genetic drift, especially if the effective population size is small (Li and Graur 1991). It is possible that some LTR elements, despite being fixed in the species, had a slight negative impact and were gradually eliminated with time. Alternatively, mechanisms unrelated to selection, such as differential rates of recombination in different GC domains, may also explain the shifting density patterns of LTR retroelements. The fact that the youngest Class II ERVs do not show the same density pattern shifts as seen for most of the LTR superfamilies could be because there has not been sufficient evolutionary time for their distribution to be shaped by selective forces and/or recombination. Once fixed in the population, it is not possible for an insertion to be eliminated unless insert-free alleles are re-created. While unequal crossing-over between 63 homologous chromosomes may be the main mechanism responsible for elimination of retroelements in G C rich regions, which have higher rates of recombination (Fullerton et al. 2001), intrachromosomal deletions and IR-mediated recombination might enhance this effect, especially in regions of high retroelement density. Such processes could regenerate insert-free alleles and again provide an opportunity for the original insertion to be lost from the population through natural selection or drift. While these studies have attempted to address some of the potential mechanisms or forces that have shaped the genomic distributions of human retroelements, further studies are warranted to elucidate the complex evolutionary and functional relationships between these sequences and their host genome. 64 Chapter 3: Analysis of transposable elements in the human and mouse transcriptomes A version of this chapter has been published: van de Lagemaat, L .N . , J.R. Landry, D.L. Mager, and P. Medstrand. 2003. Transposable elements in mammals promote regulatory variation and diversification of genes with specialized functions. Trends Genet 19: 530-536. I performed all bioinformatic analyses, except that in Table 3.2, and wrote sections of the paper. J. R. L. created Table 3.1 and Figure 3.2. D. L. M . and P. M . are senior authors on the paper. 65 3.1 Introduction TEs (primarily retroelements) comprise at least 45% of the human genome and 40% of the mouse genome and ancient elements which have diverged beyond recognition have also undoubtedly contributed to the composition of mammalian chromosomes (Deininger and Batzer 2002; Mouse Genome Sequencing Consortium 2002). While the negative effects of TEs in causing mutations in individuals are well recognized (Ostertag and Kazazian 2001; Deininger and Batzer 2002; Mouse Genome Sequencing Consortium 2002), their major impact may be their ability to induce changes in gene regulation (Murnane and Morales 1995; Brosius 1999; Hamdi et al. 2000; Medstrand et al. 2001; Nigumann et al. 2002; Jordan et al. 2003; Kashkush et al. 2003) or coding potential (Murnane and Morales 1995; Nekrutenko and L i 2001) without destroying existing gene functions. The primary goal of this study was to test the hypothesis that TEs foster variation in some gene classes while being excluded from others. 3.2 Methods 3.2.1 Prevalence of TEs in human and mouse gene transcripts Genomic coordinates of TEs and mRNAs contained in the RefSeq database were downloaded from the human June 2002 and mouse February 2003 Genome Browser at the University of California Santa Cruz ( Genes were defined by their mRNAs, which were required to have non-zero-length 5' and 3' UTRs as mapped to the sequence assemblies. We excluded 1998 human and 2557 mouse mRNAs contained in RefSeq from the analysis because they lacked either a 5' or a 3' UTR or both UTRs. 66 For each genome, we constructed mySQL databases containing the mapping data and Perl scripts that conducted automated queries to determine genomic overlaps between TEs and UTR exons. Overlaps of greater than one bp were allowed but only 2% of detected TEs had an annotated overlap of <5 bp. To eliminate false-positive TEs (which can occur in regions where the local GC content differs from the surroundings), genomic sequences of all putative repeats in UTRs were remasked using RepeatMasker ( with -s (sensitive) and -gccalc (expected GC content equal to that of the repeat itself) settings. Finally, all 490 human Alu repeat elements, identified in the sense orientation at the 3' end of transcripts, were moved to the 3' 'internal' UTR category because many appear to represent oligo-dT mispriming on the A-rich Alu terminus during cDNA synthesis. 3.2.2 Variation of TE prevalence with gene class or function The Gene Ontology (GO) analyses of RefSeq transcripts was carried out as follows: the RefSeq database was downloaded from the online NCBI repository and each record was parsed to obtain the accession numbers of the nucleotide source records of each RefSeq transcript, and these links were recorded in a database table. Further, the SwissProt database was downloaded and parsed to obtain the links between SwissProt identifiers and the accession numbers in the nucleotide database upon which each SwissProt record was based. We then also constructed a table of links between GO terms and SwissProt identifiers parsed from a table downloaded from the GO online repository ( With these tables in a large mySQL database, a three-way table join allowed us to make a classification of most RefSeq transcripts. We then also downloaded the database of GO terms and links between them and used a mySQL database system to translate the assigned GO terms to more general ones within the 67 molecular function and biological process classification trees. The conservation-based analyses of Ka/Ks were done using basic assumptions. Alignments of all mouse and all human RefSeq transcripts were constructed by finding the best human-mouse hit using ungapped BLASTn (Altschul et al. 1990). The aligned results were parsed and analyzed in three reading frames. The optimal reading frame was chosen by minimization of the sum of stop codons and non-synonymous substitutions. The Ka/Ks ratio was calculated in this reading frame. 3.3 Results and Discussion 3.3.1 Prevalence of TEs in human and mouse gene transcripts We first determined the overall prevalence of TEs in the UTRs of human and mouse genes in the RefSeq database ( This analysis revealed that 27.4% of 12179 human RefSeq loci with annotated UTRs (referred to from now on as human genes) have at least one mRNA with TE-derived sequence within the 5' or 3' UTR. The percentages of genes with TEs in different UTR locations are shown in Figure. 3.1a. These data are in general agreement with a recent survey of the Mammalian Gene Collection ( which showed that close to 20% of human genes in that dataset contain TE sequences in a 5' or 3' UTR (Jordan et al. 2003). Analysis of the mouse Refseq database in the same way revealed that 18.4% of 10064 mouse RefSeq loci (or mouse genes) contain at least one TE within their UTRs. The lower TE coverage in mouse genes is likely to be more apparent than real due to an incomplete rodent repeat database and to the higher nucleotide substitution rate in the mouse lineage resulting in fewer detectable ancient TEs in mouse compared to human 68 (Mouse Genome Sequencing Consortium 2002). (a) 0 . 2 5 , 0.20 fj 0.15-1 CO 1— 0.10-1 0.05 0 Fraction of genes with TEs in each location Human Q Mouse 5' Terminus 5 ' U T R internal 3 ' U T R internal 3 ' Terminus (b) CO c o c c (/) UJ Orientation of LTRs in genes Sense |~] Ant isense Human introns Human transcript termini Mouse introns Mouse transcript termini Figure 3.1 TEs in genes by species and orientation, (a) Fraction of human and mouse genes with TEs in UTRs. The fraction of genes with one or more RefSeq mRNA having at least one TE extending across the 5' or 3' end of the transcript ('terminus'), or totally within ('internal')the 5' or 3 ' UTR is shown, (b) Transcriptional orientation of LTR elements in introns compared to those spanning mRNA termini. The left scale is the absolute numbers of LTR elements within introns of genes and the right hand scale shows numbers overlapping mRNA termini. Note that over 99% of TEs within genes are in introns. The orientation bias of all four categories shown is significant (p<0.01). 3.3.2 TEs serve as alternative promoters of many genes A search of the Human Promoter Database ( has previously shown that close to 25% of analyzed promoter regions contain some TE-69 derived sequence (Jordan et al. 2003) and several individual cases showing a role for TEs in human gene transcription have been reported (Murnane and Morales 1995; Brosius 1999; Hamdi et al. 2000; Medstrand et al. 2001; Nekrutenko and L i 2001; Nigumann et al. 2002) Many of these cases were detected by our method and we also found numerous new examples of apparent usage of a TE-derived promoter where TE involvement has not been reported previously (see Table 3.1 for a partial list). Genes are candidates for having a TE-derived promoter i f the 5' end of their 5' UTR resides in a TE sequence and those in Table 3.1 were examined in more detail. This analysis illustrated several ways in which TE-derived promoters might contribute to gene expression, including examples of a) different expression patterns in human and mouse orthologs that correlate with the TE insertion (CYP19, TMPRSS3, H Y A L 4 , ENTPD1, CASPR4, M K K S ) ; b) the same TE insertion correlating with a tissue-specific promoter in both species (CA1, SPAM1, KLK11); c) presence of the TE in both species but apparent usage as a promoter in human only (MSLN) d) presence of the TE only in human but similar overall expression patterns as in the mouse (BAAT, SIAT1, CLDN14, M A D 1 LI) and e) a human multi-gene family where the member with a TE has a different expression pattern compared to other family members (FUT5, ILT2). 70 Table 3.1 RefSeq transcripts beginning within a previously unrecognized T E Gene Full name Functional Probable TE TE in Human Mouse role involvement in mouse" expression b expression" (Disease) human CYP19 Aromatase Estrogen LTR one of at least 6 No LTR drives very No placental synth (repro promoters high placental exp. abnormal) expression. TMPRSS3 Transmembr Serine LTR/Alu as alternate No TE form exp. Inner ear, ane protease promoter primarily in PBLs. kidney, protease, (deafness) Other forms stomach, serine 3 widespread testis HYAL-4 Hyaluronidas Hyaluronan Antisense L1/Alu as No Primarily placenta Primarily skin e4 catabolism only known promoter ENTPD1 Ectonucleosi Lymphoid LTR as 1 of 2 No LTR drives exp. in Widespread /CD39 de cell promoters & results placenta & triphosphate activation in HERV-derived N- melanoma. diphosphohy antigen terminus Overall drolase 1 expression widespread CASPR4 Contactin Brain cell LTR is one of 3 No LTR form exp. in Brain associated adhesion promoters & donates brain, testis, protein-like 4 protein N-terminus tumors. High exp. in brain & sp. cord MKKS McKusick- Chaperonin LTR/L2 as alternate No TE form in testis Widespread Kaufman (Mckusick- promoter and fetal tissues. syndrome Kaufman) Overall expr. gene widespread CA1 Carbonic Carbon LTR one of 2 major Yes LTR drives LTR drives anhydrase 1 metabolism promoters erythroid exp. erythroid exp. SPAM1 Sperm Sperm-egg Antisense ERV as Yes Primarily testis Primarily testis /PH20 adhesion adhesion only known promoter molecule 1 KLK11 Kallikrein 11 Serine MIR one of 3 Yes Widespread Brain & protease promoters & leads to prostate alt. N-terminus MSLN Mesothelin Megakaryo LTR as 1 of 2 Yes for Widespread Widespread /MPF cyte promoters & part of both but not from potentiating 5' UTR of other LTR or MIR factor transcript form; alt. promoter is an MIR BAAT Bile acid Bile metab. LTR only known No Liver Liver CoA (hyperchola promoter nemia) MAD1L1 Mitotic Cell cycle LTR as 1 of 2 No LTR form in Widespread arrest- regulation promoters tumors. Other deficient 1 (cancer) & part of 5' UTR of form widespread like 1 other form CLDN14 Claudin-14 Tight junct LTR as 1 of 2 No LTR form: Widespread component promoters melanoma /skin (deafness) and kidney, other form in liver SIAT1 Sialyltrasfera Humoral ERV one of at least No ERV form in B- cell & liver se 1 immunity 3 promoters mature B cells. exp. from Other forms in multi-various tissues promoters FUT5 Fucosyltransf Cell Antisense Alu/L1 as N/A Colon, liver. Much No mouse erase-5 adhesion only known promoter lower exp. ortholog compared to related FUTs ILT2/LIR1/ Ig-like Immune ERV as alternate N/A Only ILT known to ILTs LILRB1 transcript -2 inhibitory promoter be expressed in expanded receptor natural killer cells after human-mouse split "Presense of TE in mouse was determined by Genome Browser annotation, BLAST and dotplot alignments, "information from literature, where available, or expression databases. Expression pattern of the TE-initiated form is given if known. information from literature or databases with attention to patterns that differ from human. 71 One of the most striking examples of a TE insertion involved in new tissue-specific expression is the CYP19 gene (Table 3.1 and Figure 3.2a). CYP19 encodes aromatase P450, the key enzyme in estrogen biosynthesis and is expressed only in the gonads and brain of most mammals but the primate gene is also expressed at high levels in the syncytiotrophoblast layer of the placenta (Kamat et al. 2002). Placental-specific transcription of CYP19 is driven by a well-characterized alternative promoter located -100 kb upstream of the coding region (Kamat et al. 2002) and our analysis has revealed that this promoter is actually an endogenous long terminal repeat (LTR), a fact that has escaped previous notice (Figure 3.2a). Using genomic PCR, we found this LTR present in Old World monkeys and in one New World monkey (marmoset) (data not shown). Therefore, this insertion early during primate evolution appears to have provided a placental-specific promoter that assumed an important role in transcription of CYP19 and, consequently, in controlling estrogen levels during pregnancy. 72 (a) CYP19 Placenta Gonads Ovary 1.1 Others 2a Others 2 I * i I I ^ r t irHF + ^ MER21A 2...10 2...10 (ERVI) Erythroid Colon 1a 1 I I MER74C 1— 7 (ERVIII) Erythroid Colon 1a 1 I I —> III MER74C 1 ' - 5 (ERVIII) (c) MSLN Widespread Widespread 1a 1b 1 | | , j » - 4 III MIR MER54B MIR M E R 5 4 B 1 " 1 6 (SINE) (ERVIII) (SINE) (ERVIII) (d) BAAT Liver Liver 1 1 • 4 III — [ H H f r 2...4 2...4 MER11A (ERVII) U l i m , „ Mouse Human Figure 3.2 Examples of genes with apparent TE-dcrivcd promoters. Exon sequences derived from TEs are depicted by boxes shaded in a similar color as the element they are derived from. SINE elements are shown in green and retrovirus-like (ERV) sequences are in blue, where the thick arrows represent LTRs. The specific type of element is indicated below. Protein coding exons are represented by black boxes and non TE-derived UTRs are indicated by white boxes. Splicing of the alternative first exons is represented by broken lines. For the MSLN gene (part c), transcripts with the la exon either splice or read-through to exon lb. Alternative transcription start sites are illustrated by black vertical arrows and tissue-specific expression patterns are indicated above each promoter. Gene expression patterns were deduced from the literature and/or database sources. See Supplementary Table of van de Lagemaat et al. (2003). The figure is not drawn to scale. 73 Many other instances of putative TE-derived promoters or polyadenylation signals are worthy of mention. The high levels of carbonic anhydrase in human and mouse red blood cells (Brady et al. 1989) appear to be due to an LTR-derived promoter of the CA1 gene (Figure 3.2b). SPAM1 and H Y A L 4 , closely linked members of the same hyaluronidase gene family (Csoka et al. 2001), have different putative TE promoters giving rise to different expression patterns. For SPAM1, the E R V element is mostly deleted in mouse compared to human but the promoter region is retained, suggesting functional conservation of this segment. The human M S L N (or MPF) gene (Urwin and Lake 2000) appears to have two promoters, both of which are TE-derived. Both TE insertions are present in the mouse and rat genomes but we found no transcripts in the databases initiating from either TE in rodents (Figure 3.2c). The only apparent promoter of the liver-specific B A A T gene, which has recently been implicated in familial hypercholanemia (Carlton et al. 2003), is an ancient LTR in human but not in mouse (Figure 3.2d). FUT5 and ILT2 belong to gene families that amplified after the mouse-human divergence (Cameron et al. 1995; Martin et al. 2002). As shown in Table 3.1, these genes have putative TE-derived promoters and have acquired an expression pattern distinct from other family members, although it is not known if the TE is the cause of the differential expression. We also found many examples of TEs serving as polyadenylation sites. Disease-associated genes with primary transcripts terminating in a TE include the F8 (factor 8) gene, which is polyadenylated in an LTR and the LNG1 (or p33INGl) tumor suppressor gene, which ends in a D N A TE. We (Chapter 2, Medstrand et al. 2002) and others (Smit 1999) have observed that some classes of TEs found within introns of genes are more likely to be oriented in the 74 antisense transcriptional direction. This is particularly true for L T R elements and LI sequences and is thought to reflect the fact that regulatory motifs such as polyadenylation signals within these elements are more likely to be detrimental by, for example, leading to truncated proteins (and thus less likely to be fixed) i f oriented in the same direction as the gene. This study revealed that, in contrast to their intronic antisense orientation bias, LTR elements located at the 5' and 3' termini of both human and mouse UTRs are significantly more likely to be oriented in the same transcriptional direction as the gene transcript (Figure 3.1b). This observation supports the concept that LTR elements at transcript termini are not merely tolerated by the gene but actually participate in transcript formation by providing promoters and polyadenylation signals which function only in the sense direction. 3.3.3 TE prevalence varies with gene class or function To ascertain i f certain types of genes were more or less likely to have TE-containing mature transcripts, we used several methods to classify genes. First we used the Gene Ontology database ( to classify genes according to their biological process or molecular function and determined the fraction of human and mouse genes containing TEs in transcripts. A remarkably similar pattern in the two species emerged from this analysis. For several classes of genes, the fraction of TE-containing transcripts was significantly less than the overall average (Figure 3.3a, b). Members of these categories are involved in basic housekeeping functions and many are evolutionarily conserved with few identified paralogs (International Human Genome Sequencing Consortium 2001; Venter et al. 2001). In contrast, genes involved in functions such as defense, stress response and response to external stimuli were more likely to have TEs than most of the other gene classes (Figure 3.3a, b). 75 Bio log ica l process (b) 0.5 .5 0.4 o 2 0.3 § 0.2 I « x x x x x \ x v Molecular funct ion - Human - Mouse I • i T V \ V \ ^ <2* 3» ^ % 0.3 0.2 0.1 0 (c) Protein conservat ion 0.3 I 7>s 7'S (d) Spec ies conservat ion 0.3 i c o % Figure 3.3 Prevalence of TEs in mRNAs of various gene classes. Symbols show the observed fraction and vertical bars represent the expected fraction of genes containing a TE sequence in the UTR. This expected fraction was determined by assuming a random distribution of TEs in UTRs of all genes and by considering the number of genes belonging to each class. The expected range or length of the bar is shown for p<0.01. (a) Gene classification by 'biological process' using the Gene Ontology (GO) database ( (b) Gene classification by GO 'molecular function'. For parts a and b, the scale for human genes (blue symbols) is indicated on the left and the mouse scale (orange symbols) is shown on the right of each panel. The 'other' category includes genes of unknown function as well as those of other functional groups, (c) Human and mouse genes separated into those having a Ka/Ks ratio less than or greater than 0.115 - the median ratio reported previously for all known human-mouse orthologues (Mouse Genome Sequencing Consortium 2002). Ka/Ks values were calculated for 7296 mouse-human gene pairs in our RefSeq dataset. (d) Genes grouped using the K O G database (euKaryotic Clusters of Orthologous Groups; Human: genes found only in human (as the sole mammalian representative in the KOG database) plus gene groups conserved in other eukaryotes but expanded to 10 or more members in human. Animal: genes conserved in C. elegans, D. melanogaster, and H. sapiens. Eukaryote: genes conserved in animal, Arabidopsis thaliana (mustard weed), Saccharomyces cerevisiae (budding yeast), Schizosaccharomyces pom be ('fission yeasty, and Encephalitozoon cuniculi (Microsporidia). 76 We next classified genes using the InterPro (IPR) database of functional protein domains ( and again found good agreement between human and mouse. TEs were either significantly enriched or reduced in genes containing 33 of the 80 most abundant IPR domains. Table 3.2 shows a list of those IPR domains with at least 20 genes in the human RefSeq database and where the observed fraction of genes with TEs in UTRs differs from the expected fraction, based on a random distribution of TEs (pO.Ol). We found that transcripts of genes encoding Ig/MHC, C-type lectin or some cytokine domains were significantly enriched for TEs as were genes with K R A B / Zn-finger transcription factor domains In contrast, genes important in development, transcription and replication and those with some enzymatic domains were much less likely to include TEs in their mRNAs (Table 3.2b). 77 Table 3.2 Domains associated with TE enrichment or exclusion in mRNAs (a) Domains associated with TE enrichment InterPro Human Mouse Percentage of total genesd ID Name TE-free genes" TE-genes° T E -free genes TE-genes Hum an Mou se Fly IPR001909 KRAB boxa 36 79 (29)" 15 13(4) ** 1.7 0.7 0 IPR007087 Zn-finger, C2H2 type 202 149 (88)** 93 27 (18) ** 5.0 3.0 3.6 IPR003006 Immunoglob./ major histocompatibility complex 157 102 (65) ** 92 30 (18) ** 3.2 3.2 1.7 IPR000276 Rhodopsin-like GPCR superfamily 80 60 (35) ** 75 21 (14)** 4.6 3.9 1.1 IPR000315 Zn-finger, B-box 26 23(12) ** 6 7 (2) ** ! 0.5 0.3 0.1 IPR001304 C-type lectin 34 27(15) ** 33 15(7) ** 0.5 0.8 0.5 IPR003877 SPIa/RYanodine receptor SPRY 32 24 (14) ** 6 6(2) **! 0.5 0.3 0.1 IPR002996 Cytokinereceptor, common beta/gamma chain 10 12(6) ** 12 5(3) ! 0.2 0.3 0 (b) Domains exclusion associated with TE InterPro Human Mouse Comparative domair coverage1 ID Name TE-free genes TE-genes T E -free genes TE-genes Hum an Mou se Fly IPR000504 RNA-binding region RNP-1 (RNA recognition motif) 143 23 (42) ** 55 10 (10) 1.6 1.6 1.7 IPR001356 Homeobox 93 13(27) ** 84 6(13) ** 1.4 1.8 1.2 IPR004046 Glutathione S-transferase, C-terminal 22 0(6) ** 12 1 (2) ! 0.2 0.3 0.4 IPR000629 ATP-dependent helicase, DEAD-box 23 0(6) ** 9 0(1) ! 0.2 0.2 0.3 IPR000387 Tyrosine specific protein phosphatase and dual specificity protein phosphatase 53 6(15) ** 28 5(5) 0.6 0.7 0.4 IPR000225 Armadillo repeat 28 1(7) ** 7 0(1) ! 0.2 0.3 0.2 'Domains in bold are under reduced purifying selection or increased diversifying selection in mammals (Mouse Genome Sequencing Consortium 2002). "Observed number of genes without a T E in the UTR. "Observed number of genes with a T E in the UTR and, in parenthesis, expected number of genes with a TE assuming a random distribution of TEs in UTRs of all genes. "Indicates cases where the observed number differs from the expected with p < 0.01 (chi-squared). ! Indicates less than 20 genes in RefSeq. "Percentage of total genes with the domain in the genomes of the species listed using the Ensembl gene classification ( Significant domain expansions (p<0.01 for chi-squared considering the number of genes in each species) for human vs. fly and mouse vs. fly are indicated in bold. 78 3.3.4 TEs are more prevalent in mRNAs of rapidly evolving and mammalian-specific genes TE prevalence in UTRs was next determined in genes separated according to their sequence conservation, measured by their Ka/Ks value, which is the ratio of the rate of nonsynonymous to synonymous change in coding sequences (Hurst 2002). A median Ka/Ks value of 0.115 for mouse-human orthologous gene pairs was recently determined (Mouse Genome Sequencing Consortium 2002) and, relative to this median, we found that genes with low Ka/Ks values are significantly less likely to have TEs in UTRs compared to those with values above the median (Figure 3.3c). These results indicate that genes with rapidly-evolving coding sequences are, in general, more likely to have TEs in their UTRs. Earlier analysis showed that at least eight functional domains are under increased positive diversifying selection or reduced purifying selection based on their high Ka/Ks ratio of >0.15 (Mouse Genome Sequencing Consortium 2002). Three of these domains are also significantly associated with genes with TE overrepresentation in their UTRs and these are bolded in Table 3.2a. Furthermore, it is noteworthy that 6 out of 8 domains associated with enrichment of TEs in genes (Table 3.2a) are represented at significantly higher numbers in mammalian genomes compared to the fruit fly (Drosophila melanogaster), whereas four of the six domains associated with a reduced TE-content in UTRs are equally represented in human and mouse vs. fly. Taken together, these data suggest that TEs are preferentially found in mRNAs containing rapidly diversifying domains, many of which have expanded during vertebrate evolution. Finally, we examined TE prevalence in genes divided into three categories (eukaryotic, animal and human) based on presence of orthologous proteins in different 79 species using the euKaryotic Clusters of Orthologous Groups (KOG) database ( This analysis showed that mammalian (human)-specific gene mRNAs are significantly enriched in TEs compared to transcripts of genes with orthologs in other animals and/or all eukaryotes. This enrichment was most apparent when we expanded our definition of mammalian-specific genes to include all genes with an ancient origin but which have expanded in humans (and likely other mammals) (Figure 3.3d). Transcripts of 'old' gene classes that are not expanded in mammals have a low prevalence of TEs, while genes specific to mammals or those associated with mammalian expansions are significantly more likely to harbor TE sequences in their mRNAs. We considered two simple reasons for the above patterns. First, we addressed the possibility that TE prevalence in mRNAs is fully or partially dependent on genomic features rather than on gene function. For example, TEs are rarely found in UTRs of genes with homeobox domains (Table 3.2b), an expected observation given that the genomic regions encompassing the human and mouse homeobox gene clusters are nearly devoid of TEs (International Human Genome Sequencing Consortium 2001; Mouse Genome Sequencing Consortium 2002). We grouped genes by functional class and found that genomic parameters, such as number of TEs available, TE density, gene size, number of exons, length of introns, and local GC content, were insignificantly different between the functional groups. Correlation analysis confirmed this observation, demonstrating that a gene's functional category and its genomic surroundings independently influence the number of TEs within UTRs (data not shown). Second, we considered the possibility that transcripts enriched in TEs are more likely to be derived from non-functional but expressed pseudogenes. To address this possibility, we 80 separated RefSeq loci into two categories, 'reviewed' and 'provisional', which represent relatively well documented genes, and 'predicted', for which the support is less strong ( We obtained similar TE frequencies with these two gene sets. Thus, neither genomic features nor the presence of pseudogenes fully account for the observed patterns shown in Figure 3.3 and Table 3.2. Rather, the data suggest that gene function and conservation act as independent variables in determining TE prevalence in mRNAs. 3.4 Conclusions A growing appreciation for the role of TEs in genome evolution and gene regulation is evident from a number of recent studies (Murnane and Morales 1995; Sverdlov 1998; Brosius 1999; Hamdi et al. 2000; Makalowski 2000; Kidwell and Lisch 2001; Medstrand et al. 2001; Nekrutenko and L i 2001; Ostertag and Kazazian 2001; Deininger and Batzer 2002; Mouse Genome Sequencing Consortium 2002; Nigumann et al. 2002; Jordan et al. 2003; Kashkush et al. 2003). Here we have shown that highly conserved genes, such as those with essential functions in metabolism, development or cell structure, have a low prevalence of TEs in their mRNAs. This finding suggests, as might be predicted, that changes in expression of fundamental genes due to TE insertions cannot be allowed by the host and are strongly selected against. In contrast, younger or mammalian-specific genes, such as those involved in immunity and those that have expanded during mammalian evolution, are enriched for TEs in their mRNAs. It is possible that due to functional redundancy, such genes are initially more tolerant of TE insertions, some of which may then evolve a role in gene expression. These results suggest the TEs have had a major impact on the rapid evolution and functional diversification of gene families in humans and other mammals. 81 Chapter 4: Analysis of genie distributions of endogenous retroviral long terminal repeat families in humans A version of this chapter has been submitted for publication: van de Lagemaat, L .N . , P. Medstrand, and D.L. Mager. 2006. Insertion patterns of endogenous retroviruses and S V A elements: Insights into their initial effects on genes. I planned and performed all analyses in this paper and wrote the paper P. M . was involved in planning this research and writing the paper D. L. M . helped plan research and is the senior author 82 4.1 Introduction Transposable elements (TEs), including endogenous retroviruses (ERVs), have profoundly affected eukaryotic genomes (Kidwell and Lisch 1997; Deininger and Batzer 2002; Kazazian 2004). Similar to exogenous retroviruses, E R V insertions can disrupt gene expression by causing aberrant splicing, premature polyadenylation, and oncogene activation resulting in pathogenesis (Boeke and Stoye 1997; Rosenberg and Jolicoeur 1997; Maksakova et al. 2006). While ERV activity in modern humans has apparently ceased, about 10% of characterized mouse mutations are due to E R V insertions (Maksakova et al. 2006). In rare cases, elements that become fixed in a population can provide enhancers (Ting et al. 1992), repressors (Carcedo et al. 2001), alternative promoters (Di Cristofano et al. 1995; Medstrand et al. 2001; Dunn et al. 2003; Jordan et al. 2003; van de Lagemaat et al. 2003, Chapter 3; Bannert and Kurth 2004; Leib-Mosch et al. 2005) and polyadenylation signals (Mager et al. 1999; Baust et al. 2000) to cellular genes due to transcriptional signals in their long terminal repeats (LTRs). It has been previously shown that LTRs/ERVs fixed in gene introns are preferentially oriented antisense to the gene's transcriptional direction (Smit 1999; Medstrand et al. 2002; Cutter et al. 2005). In contrast, studies on initial insertion patterns of exogenous retroviruses or retroviral vectors in vitro have not found any such bias for these unselected insertions (Schroder et al. 2002; Barr et al. 2005). Therefore, the antisense bias exhibited by fixed ERVs/LTRs in genes strongly suggests that retroviral elements found in the same transcriptional orientation within a gene are much more likely to have a negative effect and be eliminated from the population by selection. In this study, we closely examined genie distribution patterns of individual ERV families in the human genome and find 83 J significant differences. These differences provide clues to the original activity profile of each element type, helping to explain nascence of biases in patterns of insertion. 4.2 Methods 4.2.1 Directional bias of insertions in transcribed regions in mice We assessed the transcriptional orientation of Early Transposon (ETn) LTR retroelements in mouse transcribed regions. Retroelement and gene annotation from the April 2004 UCSC Mouse Genome Browser (Karolchik et al. 2003) was used to assess insertion frequency and orientation of insertions within the longest RefSeq transcribed regions of mouse genes. ETn LTR elements were represented by the R L T R E T N family of ETn/MusD LTRs, and pairs of elements within 10 kb of each other and in the same orientation were assumed to belong to the same original insertion. The antisense bias observed in the genie ETn LTR population was then compared to genie orientation bias in a data set of documented mutagenic ETn/MusD LTR insertions coming from earlier studies (Baust et al. 2002; Mouse Genome Sequencing Consortium 2002; Maksakova et al. 2006). 4.2.2 Directional bias of retroelements in the human genome RepeatMasker annotations of solitary LTRs and LTRs plus internal sequences of endogenous retroviral elements from the July 2003 UCSC Human Genome Browser were compiled and compared to annotated transcribed region start and end points of the per-chromosome longest transcript of each RefSeq gene, defined by its HUGO gene name. Annotations for internal elements were matched with their respective LTRs as follows: H E R V E or Harlequin internal sequences were matched with LTR2, LTR2B, or LTR2C; H E R V K (HML-2) with LTR5, LTR5_Hs, LTR5A, or LTR5B; HERV17 with 84 LTR 17 (where HERV17 represents HERV-W); H E R V H with LTR7, LTR7A, or LTR7B; HERV9 with LTR12, LTR12B, LTR12C, LTR12D, LTR12E, or LTR12_; MLT2x with ERVL-x (where x is a unique identifier); MST* with MST*-int (where * represents a wildcard); THE1* with THEl*-int; and MLT1* with MLTl*- int . Groups of LTR element segments of the same type, with internal sequence all in the same orientation, and occurring within 10 kb were deemed part of the same composite element. Manual checks confirmed the validity of this criterion. Names of consensus elements occurring in each composite element were recorded, as well as names of the E R V type. Composite elements without internal sequence were deemed LTR-only, and elements with contributions from at least two consensus elements were deemed to contain LTR and internal sequence and therefore were considered full-length. Again, manual checking confirmed the validity of this criterion. The assigned genomic position of each LTR or full-length element was computed as the average of the beginning and end coordinates of each composite element and compared against the positions of longest transcribed regions of each gene. Each transcribed region was divided into ten equal bins and the TE location within a gene was specified by which of these bins it fell into. In addition to the ten intragenic bins, two bins upstream and two bins downstream of the gene, of the same size as the intragenic bins, were also considered. Counts of elements for each orientation were computed for each bin. A similar approach was used for computing S V A and Alu distributions across genes as for LTR elements. 85 4.3 Results and Discussion 4.3.1 Opposite orientation bias of fixed versus mutation-causing retroviral insertions As mentioned above, in vitro studies of de novo retroviral insertions within gene introns have not detected any bias in proviral orientation with respect to the transcribed direction of the gene (Schroder et al. 2002; Barr et al. 2005). The fact that integrations that have not yet been tested for deleterious effect during organismal development show no directional bias indicates that the retroviral integration machinery itself does not distinguish between D N A strands in transcribed regions. Presumably, then, any orientation biases observed for endogenous retroviral elements must reflect the forces of selection. In support of this premise is a recent study by Bushman's group that was the first to directly compare genomic insertion patterns of exogenous avian leukosis virus (ALV) after infection in vitro with patterns of fixed endogenous elements of the same family (Barr et al. 2005). Endogenous elements in transcriptional units were four times more likely to be found antisense to the transcriptional direction, suggesting strong selection against A L V in the sense direction. We reasoned that, i f the marked orientation biases of LTRs/ERVs were a reflection of detrimental impact by sense-oriented insertions, then we would also expect a dominant sense orientation among insertions with known detrimental effects. While no mutagenic or disease-causing E R V insertions are known in humans, significant numbers have been studied in the mouse. We analyzed element orientation of fixed, non-pathogenic insertions of the still active ETn/MusD family of ERVs in the mouse (Figure 4.1), and found similar degrees of antisense bias as seen for human and chicken ERVs (data not shown). However, as expected, 15/18 new mouse germ-line ETn/MusD insertions in transcribed regions that are associated with mutations are in the sense orientation (Maksakova et al. 2006) (Figure 4.1). Moreover, in 86 most of these cases, the predominant effect of the ERV was to cause premature polyadenylation of the gene through use of LTR polyA signals, accompanied by aberrant splicing (Maksakova et al. 2006). • Sense OAnt i Mouse-all Mutagenic Figure 4.1 Directional bias of retroelements in mouse transcribed regions. ETn elements were those annotated as RLTRETN in the UCSC May 2004 mouse genome repeat annotation. The mutagenic population of ETn elements was reported in earlier reviews (Baust et al. 2002; Mouse Genome Sequencing Consortium 2002; Maksakova et al. 2006). Expected variability in the data was calculated from Poisson statistics, which describe randomized gene resampling. 4.3.2 Variation in density of genie insertions of different HER Vfamilies ERVs/LTR elements in the human genome actually comprise hundreds of distinct families of different ages and structures, many of which remain poorly characterized (Gifford and Tristem 2003; Mager and Medstrand 2003). Thus, grouping such heterogeneous sequences together, as has been done for previous studies on orientation bias (Smit 1999; Medstrand et al. 2002), may well mask variable genomic effects of distinct families. To investigate genie insertion patterns of different human ERV families, we chose nine well studied Repbase-annotated (Jurka 2000) families or groups of related families to analyze in more detail. These families, their copy numbers and their approximate evolutionary ages are listed in Table 4.1. 87 Table 4.1 Annotated copy numbers and evolutionary ages of various E R V familes Name copy full evolutionary Reference number3 length" age(Myr) MLT1 160,000 36,000 >100 (Smit 1993) MST 34,000 5175 75 (Smit 1993) THE1 37,000 9019 55 (Smit 1993) H E R V - L 25,000 4777 >80 (Cordonnier et al. 1995) HERV-W 675 242 40-55 (Blond etal. 1999) HERV-E 1138 294 25 (Taruscio et al. 2002) H E R V - H 2508 1284 >40 (Jern et al. 2004) HERV9 4837 697 15 (Costas and Naveira 2000) H E R V - K 1206 178 30 (Bannert and Kurth 2004; (HML2) Belshaw et al. 2005) "Including LTRs with no internal sequence and LTRs with associated internal sequence "Elements including both LTR and internal sequence As a first step, we plotted the fraction of total elements in either orientation found within RefSeq (http:// transcriptional units (see Methods) and the results are shown in Figure 4.2. To put our results in context, we considered a model of random initial integration throughout the genome. Since 34% of the sequenced genome falls within our analyzed set of RefSeq transcriptional units, we would expect 34% of E R V insertions, 17% in either direction, to be found in these regions. This is a conservative model since initial integration patterns of most exogenous retroviruses are biased toward genie regions (Panet and Cedar 1977; Schroder et al. 2002; Mitchell et al. 2004; Barr et al. 2005) (see also below). An earlier study (Medstrand et al. 2002) noted that, for large superfamilies of LTR elements, elements in either orientation are less prevalent in genie regions than expected by chance. In the present study, we were particularly interested in the fact that, for many LTR types, there are fewer antisense LTRs than expected by chance. This may be a reflection of enhancer effects by these 88 elements, an effect often seen in mice and reviewed elsewhere (Rosenberg and Jolicoeur 1997). Closer analysis of our chosen individual families revealed significant variation in the magnitude of this effect (Figure 4.2). For example, antisense LTRs of the MLT1 and H E R V - K (HML-2) families are relatively more prevalent in genes, suggesting that the presence of these sequences in the antisense direction is less likely to negatively affect the enclosing gene. A n alternative explanation is that the initial integration preference of these families was biased more heavily to transcriptional units, compared to most other families. The density patterns of most of the other families are qualitatively similar to each other, with a moderate, though significant, under-representation of antisense elements and a further 2 to 3 fold reduction in sense elements. Similarly, a recent study of a chimpanzee-specific family of gammaretroviruses by Yohn et al (2005) showed that all 13 of these ERVs found within transcribed regions were oriented antisense to the direction of gene transcription. The exception to this pattern is HERV9 (ERV9), which will be discussed further below. 0.2 c o fj 0.15 + • | 0.1 + o § 0.05 + ^ & A-Element type 0 Figure 4.2 Orientation bias of various full length ERV sequences in genes. ERV families are as annotated by RepeatMasker in the human genome and are listed in Table 4.1. Fraction of all genomic elements actually found in genes in the sense and antisense orientations is presented, with neutral prediction (dotted line) based on fraction of total genomic elements expected in sense and antisense directions in genes under assumption of uniform random insertion. 89 4.3.3 Density profiles of ER Vs across transcriptional units At least three factors could account for the antisense bias exhibited by most ERV families. First, the sense-oriented polyadenylation signal in the LTR could cause premature termination of transcripts and therefore be subject to negative selection. Gene transcript termination within LTRs commonly occurs in ERV-induced mouse mutations (Maksakova et al. 2006) and this effect has been proposed as the most likely explanation for the orientation bias (Smit 1999). Second, splice signals within the interior of proviruses could induce aberrant RNA processing, a phenomenon also frequently observed in mouse mutations (Maksakova et al. 2006). To test this second possibility, we plotted graphs similar to Figure 4.2 separately for solitary LTRs, which comprise the majority of retroviral elements in the genome (International Human Genome Sequencing Consortium 2001; Mager and Medstrand 2003), and for composite elements containing LTR and internal sequence (data not shown). While the numbers of the latter are much lower than for solitary LTRs for most families, we detected no significant differences in the density patterns, suggesting that signals within the LTRs, and not interior splice signals, are the primary determinant of the orientation bias. A third factor that could result in orientation bias is the presence of the LTR transcriptional promoter with a potential to cause ectopic expression of the gene, resulting in detrimental consequences, as occurs in cases of oncogene activation by retroviruses (Rosenberg and Jolicoeur 1997). If introduction of an L T R promoter was the primary target of negative selection, one would predict that sense-oriented LTRs located just 5' or 3' to a gene's native promoter would be equally damaging and therefore subject to similar degrees of selection. 90 To look for evidence of these effects, and to more closely examine the distributions of ERVs within genes, we measured the absolute numbers of ERVs/LTRs of different families in bins across the length of RefSeq transcriptional units and in equal-sized bins upstream and downstream (see Methods). The results of this analysis (Figure 4 . 3 ) revealed density profiles that shift dramatically at gene borders. Specifically, for most ERV families, we found that the prevalence of sense-oriented elements drops markedly inside the 5 ' terminus of a gene, remains relatively low across the gene and then jumps just as markedly 3 ' of the gene. This type of pattern does not indicate a strong detrimental effect of LTR sense-oriented promoter motifs. Rather, these profiles suggest that presence of the LTR polyadenylation signal, which would generally only affect a gene if located within its transcriptional borders, is the regulatory signal primarily responsible for the resulting lack of sense-oriented LTR elements within introns. 91 MLT1 3500 30001 • 2500 ' 1 2000-1500-1000 -j 500-I 0 oo E * * * • • * • — i — i — i — i — i — 0 2 4 - i — i — i — i — i 8 +1 700 600 500 400 H 300 200 100 0 THE1 - i — i — i — i — i — i — i — i — i — i — i — i — i 0 2 4 6 8 +1 HERVW 40 -I 35 + 30 0) 25 O 204 X ! E 3 15 + 10 • 5 H 0 • -2,-1 120-1 0 0 ^ 80 i 60 • 40 • 20 • 0 • -2,-1 60 50 i 40 t 30 20 -j 10 -I * I i i i i —i 1 1 1 » 1 0,1 2,3 4,5 6,7 8,9 +1 +2 HERVH i 5 0,1 2,3 4,5 6,7 8,9 +1.+2 HERVK * j I i * h i i i i i i 0 • -2,-1 — i 1 1 1 1 1 0,1 2,3 4,5 6,7 8,9 +1 +2 700 600 500 400 300 H 200 100-| 0 * • 2 MST • • • . I * * * c 500 400 300 200 100 0 i — i — i — i — i — i — i — i — i — i — i — i — i •2 0 2 4 6 8 +1 HERVL * • • • • • • • -T 1 1 1 1 1 1 1 1 1 1 1 -2 70 -. 60 :•• II 50 40 -30 -20 -10 -0 0 2 4 ( HERVE 8 +1 * i f T 1 1 1 1 1 2,-1 0,1 2,3 4,5 6,7 8,9 +1 +2 HERV9 140-i 120 4 100 I 1 80 T I 60 40 20 H 0 i T 1 1 1 1 1 1 1 1 1 1 1 1 2 0 2 4 6 8 +1 IAnti •Sense Transcription unit bins Figure 4.3 Patterns of annotated ERV presence in equal-sized bins across transcriptional units. Ten bins, numbered 0-9, were considered within transcribed regions. Four bins, two in either direction outside gene borders and equal in length to intragenic bins, were considered, and are shown as bins -2 and -1 upstream and +1 and +2 downstream. 92 4.3.4 Distinct pattern of HER V9 elements with respect to genes By separating ERVs into different families, we uncovered a unique genie distribution pattern of HERV9 elements. As shown in Figure 4.2, HERV9 has a more significant deficit of antisense elements and little orientation bias compared to other E R V families. The distinct HERV9 density profile across gene regions illustrates the same point in greater detail (Figure 4.3H). These data suggest that HERV9 elements within introns are nearly equally likely to adversely affect the gene, regardless of orientation. This is the only HERV family we have analyzed that displays this type of distribution pattern and is likely the result of the complex structure of HERV9 LTRs. These LTRs are 0.7-1.5 kb long and extraordinarily rich in the CpG dinucleotide - examination of the consensus elements from RepBase (Jurka 2000) reveals that all HERV9 LTR (LTR 12, in RepBase nomenclature) subfamily members are CpG rich, with approximately 90 CpGs spread over the consensus of the most-abundant LTR12C LTR. A relatively CpG-poor tract in the LTR's U3 region contains 5-17 repeats of a sequence rich in transcription factor binding sites, which have recently been shown to bind a transcription factor complex involved in the regulation of the beta globin locus (Yu et al. 2005). HERV9s are under-represented in both orientations in all bins within transcribed regions compared to the nearest regions upstream and downstream of genes. These results suggest exclusion of these ERVs from genie regions in both orientations, likely due to a transcription defect similar to simple polyadenylation. However, analysis for polyadenylation signals using DNAFSMiner (Liu et al. 2005) reveals the presence of polyadenylation signals in all LTR12 family consensus sequences and the absence of a polyadenylation signal on the opposite strand, suggesting that polyadenylation alone cannot account for this distribution pattern. One possible explanation comes from recent 93 work by Lorincz et al (2004), which showed that methylated intragenic CpG dinucleotides were associated with transcriptional elongation defects, likely due to induction of a closed chromatin formation. This observation, coupled with the fact that HERV9 LTRs are CpG rich, has the potential to explain strong selection against intragenic insertions of HERV9 LTRs in either orientation. 4.3.5 SVA SINE elements display distribution patterns similar to LTRs S V A elements are composite SINE sequences composed of a tandem hexamer repeat, a partial Alu element, a variable number of tandem repeats, a partial E R V - K LTR, and a poly-A tail (Ono et al. 1987; Zhu et al. 1992; Shen et al. 1994; Wang et al. 2005). These elements contain an internal promoter and the LTR-derived poly-A signal. Like Alu elements (Dewannieux et al. 2003), S V A elements are thought to utilize LI-encoded machinery to retrotranspose (Wang et al. 2005). S V A elements are a relatively young and actively transposing family in humans and have caused several mutations (Ostertag et al. 2003; Chen et al. 2005). These elements have a stronger antisense bias in genie regions, compared to AluY elements (Figure 4.4A, C), suggesting interference with pol II transcriptional machinery. Similar to in vitro insertions of exogenous viruses (discussed above), antisense SVAs are found in transcribed regions more frequently than expected by random chance, suggesting that genie regions are favored targets for S V A insertions. Analysis of the profiles of sense and antisense S V A elements across transcription units revealed that, as with LTR elements, there was a drastic change in antisense bias at the boundaries of transcribed regions, mostly due to a sudden drop in density of sense-oriented insertions. This low density of sense-oriented insertions persisted across transcriptional units (Figure 4.4B), again suggesting that polyadenylation plays a significant role in deleterious consequences of germline S V A insertions. 94 A SVA B Transcription unit bins - - - Expected [] oSense | " A n t i Figure 4.4 Insertion pattern of SVA and AluY retroelements across transcriptional units. A,C. Fraction of annotated genomic SVA and AluY elements found in the sense and antisense directions in transcribed regions. Dotted line shows expected fraction (17%) assuming initially uniform random insertion. B, D. Cumulative insertions of SVA and AluY elements in ten bins, numbered 0-9, across transcriptional units. Similar to Figure 4.3, four extra bins were considered, two in either direction upstream and downstream of genes, and denoted -2, -I, +1 and +2. In contrast to SVAs, the AluYs, which comprise the youngest superfamily of Alu elements (International Human Genome Sequencing Consortium 2001), have a significantly smaller antisense bias, both overall, and across transcriptional units (Figure 4.4C, D). Given the similar mechanism by which SVAs and Alus have likely inserted, these results suggest that intronic insertions of Alus in both orientations have been significantly less likely to be selected against than sense-oriented insertions of SVAs. An intriguing feature of both the S V A and Alu distribution profiles across transcriptional 9 5 units is the slightly higher prevalence of sense-oriented elements in the 5' regions of genes (bins 0-3) compared to more 3' regions. This pattern could reflect original insertion site preferences favoring the 5' parts of genes. The biochemical mechanisms are unclear but could be analyzed using in vitro retrotransposition assays. It is interesting to note that SVAs, which also have a large numbers of CpG dinucleotides, do not show a similar pattern to HERV9 LTRs. CpG dinucleotides in genomic S V A elements do appear to be methylated, given their accelerated mutation rate relative to non-CpG sites (Wang et al. 2005). Why these elements fail to cause a potential elongation defect is unclear and requires further analysis, perhaps using experimental approaches. 4.4 Concluding remarks The preferential antisense orientation of LTRs/ERVs fixed in gene introns has been shown before (Smit 1999; Medstrand et al. 2002; Cutter et al. 2005). However, patterns of in vitro insertions by exogenous retroviruses have not demonstrated this bias (Schroder et al. 2002; Barr et al. 2005). Using patterns of insertions across transcribed regions for individual families, we have shown that individual ERVs have had differing impacts upon original insertion. A feature that most share, however, is deleterious impact by the polyadenylation signal, evidenced by the sharp increase in antisense bias immediately downstream of the start of transcription, corresponding to sharp decrease in the density of sense-oriented insertions. The anomalous insertion pattern of HERV9 in transcribed regions suggests an adverse impact on genes regardless of orientation, perhaps due to induction of closed chromatin as a result of methylation of its many CpG dinucleotides. However S V A elements, which are similarly rich in the CpG dinucleotide, show a robust antisense bias. In conclusion, although some functions of LTRs, primarily their 96 promoters, may have been inactivated or repressed, modern patterns of insertions can be used to deduce original selective forces acting on these elements. Furthermore, LTR sequence, presumably mobilized as part of the still active S V A SINE, continues to have an LTR-like impact on the human genome. 97 Chapter 5: Analysis of repeats and genomic stability A version of this chapter has been published: van de Lagemaat, L . N . , L. Gagnier, P. Medstrand, and D.L. Mager. 2005. Genomic deletions and precise removal of transposable elements mediated by short identical D N A segments in primates. Genome Res 15: 1243-1249. I performed all bibinformatic analysis and wrote sections of the paper. L. G. performed PCR assays. P. M . and D. L. M . discussed research and wrote sections of the paper. 98 5.1 Introduction Current genome size in mammals and other eukaryotes has been greatly affected by massive amplifications of transposable elements (TEs) or retroelements throughout evolution (Brosius 1999; Kidwell 2002; Liu et al. 2003). In mammals, close to 50% of the genome is recognizably TE-derived (International Human Genome Sequencing Consortium 2001; Mouse Genome Sequencing Consortium 2002; Rat Genome Sequencing Project Consortium 2004) and in some plant species, the figure is nearly 80% (SanMiguel et al. 1998; L i et al. 2004). The various classes of TEs and their distributions in genomes have been widely studied in many species (Adams et al. 2000; International Human Genome Sequencing Consortium 2001; Aparicio et al. 2002; Kidwell 2002; Mouse Genome Sequencing Consortium 2002; Y u et al. 2002; Kirkness et al. 2003; Baillie et al. 2004; Ma and Bennetzen 2004; Rat Genome Sequencing Project Consortium 2004). In contrast, much less is known about mechanisms that attenuate genome size. Studies in plants have shown that retroelement-driven genome expansion is counteracted by deletions within retroelements, likely mediated by illegitimate recombination between short flanking segments of identity (Devos et al. 2002). Comparison of related rice genomes has also revealed that illegitimate recombination has deleted both retroelement-derived sequences as well as unique nuclear D N A (Ma and Bennetzen 2004). A number of studies have documented the prevalence of small deletions and insertions (indels) in primate genomes (Britten et al. 2003; Liu et al. 2003; Watanabe et al. 2004) but there has been no genome-wide analysis to determine the molecular mechanisms which generate these events. Recent availability of the chimpanzee draft 99 sequence has afforded the opportunity to analyze the spectrum of genomic deletions that have occurred in the last 5-6 million years of primate evolution. Moreover, a large-scale comparison of the human and chimpanzee genomes allows examination of the genomic stability of retroelement insertions, which are generally considered to be irreversible with no known mechanism for precise excision from the genome (Hamdi et al. 1999; Roy-Engel et al. 2001; Batzer and Deininger 2002; Salem et al. 2003a; Salem et al. 2003b). Due to this 'unidirectional' property, retroelements, particularly Alu elements, are widely viewed as ideal markers for human population genetic studies (Carroll et al. 2001; Roy-Engel et al. 2001; Batzer and Deininger 2002; Salem et al. 2003a) and elucidation of primate phylogenetic relationships (Hamdi et al. 1999; Salem et al. 2003b; Gibbons et al. 2004). In primates, Alu sequences are the most abundant family of retroelements, comprising over 10% of the human genome (International Human Genome Sequencing Consortium 2001; Batzer and Deininger 2002). While most of the one million Alu elements retrotransposed over 40 million years ago, several thousand have integrated into the human genome since divergence from the great apes and close to a thousand of the youngest Alus are polymorphic (Carroll et al. 2001; Roy-Engel et al. 2001; Batzer and Deininger 2002; Salem et al. 2003a; Bennett et al. 2004). Most are associated with flanking direct repeats or target site duplications (TSDs) of 10-20 bp (Jurka 1997). In this study, we have obtained evidence that Alu elements can be precisely deleted from the genome via recombination between these flanking repeats. Similarly, a significant fraction of 200-500 bp deletions of non-repetitive sequence have likely taken place due to recombination between short regions of identical sequence flanking the deleted fragment. We demonstrate that this fraction is much greater than expected i f blunt-end joining were responsible for generating all these deletions. Our results are in agreement with a model 100 of genomic deletion occurring both by non-homologous and error-prone homology-driven mechanisms of D N A double strand break repair (Helleday 2003). 5.2 Methods 5.2.1 Direct assessment of retroelement deletion rate Putative retroelement insertions were obtained from the chimpanzee scaffold alignments to the UCSC July 2003 human genome (Kent et al. 2002) using RepeatMasker (A.F.A. Smit & P. Green, unpublished data), MaskerAid (Bedell et al. 2000), and libraries from the RepBase Update (Jurka 2000). Pseudogenes were detected using B L A T (Kent 2002) and the human RefSeq mRNA records. Insertions were defined as having a single retroelement (including pseudogenes) filling all but up to 90 bp of the indel and not extending beyond the indel by more than 10 bp on either side. Search queries were then constructed of the 50-bp sequences upstream and downstream of each putative retroelement insertion location. Scripted discontiguous megablast searches of the relevant NCBI trace archive were then carried out using perl scripts and the QBLAST application programming interface (; (Altschul et al. 1990; McGinnis and Madden 2004). Our B L A S T queries used a non-coding template of size 21 and required only one seed hit per high-scoring segment pair. To minimize false positives and ensure non-redundant hits, we required that 75% of the query be free of known human repeats. Further, the accepted hits were required to match the query at least 30 bp on either side of the putative breakpoint. A l l traces not fulfilling these requirements were ignored. Deletions in human relative to chimpanzee or vice versa were diagnosed by the presence in Rhesus of an insertion at least 80% of the size expected and no traces with 101 less than this amount of sequence. A site was considered an insertion if one or more Rhesus traces matched the empty site and no traces had extra sequence. Putative deletions in human or chimpanzee were further individually aligned with their Rhesus counterpart using ClustalW version 1.82 (Higgins et al. 1996) and the alignments were edited using Jalview (Clamp et al. 2004) to check for the presence of the same element in the expected position in the Rhesus trace. The alignments are provided in Appendix A. 5.2.2 Detection of deletions internal to Alu elements A l l indel loci in the chimpanzee scaffold alignments to the UCSC July 2003 human genome, masked as described above, were reanalyzed. Deletions occurring entirely within Alu elements were analyzed for involvement of the approximately 80 bp and 50 bp internal homologies. Putative deletions occurring between the 80 bp similar regions were detected by having one deletion endpoint occurring within positions 1-84 of the consensus and the other endpoint within positions 136 to 219. Similarly deletions between positions 85-135 and 219 to the end of the consensus were considered as occurring between the 50-bp similar regions. 5.2.3 Assessment of deletion frequency due to illegitimate recombination Human chromosomal sequence files with human repeats pre-masked to lower case by RepeatMasker were used. These files were further masked using Tandem Repeats Finder 3.21 (Benson 1999). A l l repetitive sequence was excised, including human repeats and tandem repeats. We then constructed a C++ program that used an alignment method to find all nonredundant nonadjacent identical segments up to 20 bp long between 200 and 500 bp apart in the nonrepetitive genome. These were tallied by length, giving the expected distribution of potential sites for illegitimate recombination in this distance 102 range. We then analyzed all fully-sequenced insertions and deletions (indels) 200-500 bp long present in the alignments of the UCSC July 2003 human sequence to the chimpanzee scaffolds (Kent et al. 2002) for the presence of flanking identical segments beginning at the deletion breakpoints. Specifically, indels with 50 bp flanking sequence on each were analyzed, and those containing putative new retroelement insertions, tandem duplications, or flanking homologous retroelements corresponding to the indel breakpoints were removed from consideration, as were all indels occurring inside transposable elements. The remaining indels were classified as deletions. Retroelement insertions were detected as described above. Other insertions were diagnosed if the indel internal sequence was found by B L A T elsewhere in the human genome. Tandem duplications were diagnosed by running Tandem Repeats Finder (Benson 1999) on a sequence including the indel extra sequence and equivalent lengths of sequence flanking the indel upstream and downstream. A n indel was considered to be a case of tandem duplication i f a tandem duplication was found covering one of the breakpoints and extending to within one bp of the other. Manual checks confirmed the validity of this criterion. After disqualifying putative insertions, tandem duplications, and indels with flanking homologous repeats, the remaining 1927 indels were termed random deletions and were analyzed for the distribution of flanking repeat sizes. Flanking repeats were considered to begin at the breakpoint positions and consist of a tract of identical sequence. No mismatches in the flanking repeat or offsets of the identical segment from the indel breakpoints were allowed. 5.2.4 Genomic PCR and sequencing Primate genomic D N A was isolated from various cell lines as described 103 previously (Goodchild et al. 1993). Additional chimpanzee D N A samples were kindly provided by Dr. Peter Parham (Stanford University). 150 ng of human or primate genomic D N A was amplified in a 50ul reaction with 200uM each dNTP, 200nM each primer (see Appendix A), 1.5mM MgC12, and 1 unit of Platinum Taq (Invitrogen) in IX PCR buffer (Invitrogen). The conditions for the PCR were 94°C for 1 min followed by 30 cycles of the amplification step (94°C for 30 s, 48-60°C for 30 s, and 72°C for 30s-1 min). The annealing temperature and extension time varied for different primer combinations. Sequencing was performed directly on PCR products using the BigDye Terminator v3.1 Cycle Sequencing Kit (ABI) in an ABI PRISM® 3730XL D N A Analyzer system at the McGi l l University sequencing facility. 5.3 Results and Discussion 5.3.1 Direct assessment of retroelement deletion frequency During an analysis to identify transposable element (TE) insertions that occurred after divergence of human and chimpanzee, we detected some apparent insertional differences involving Alu elements of older subfamilies. The AluY subfamily is the only family known to have been active in the last few million years of human evolution (Batzer and Deininger 2002). However, we identified 187 Alu elements from older families such as AluS and AluJ (98 in human and 89 in chimpanzee) which appeared to be insertional differences. This finding raised the possibility that at least some of these cases represent deletions in one species rather than new insertions in the other. To explore this possibility, scripted blast searches of the Rhesus macaque whole-genome shotgun trace archive were used to assess the ancestral state of apparent retroelement insertional 104 differences in humans and chimpanzees (see Methods). It should be noted that our requirement that 75% of the totally 100 bp flanking sequence be free of known repeats resulted in only 8389 of 14765 retroelement loci being tested, and therefore we expect that our findings represent an underestimate of the overall level of precise deletion of retroelements. Of 7120 human-chimp indel sites with accepted Rhesus trace matches, 7010 were identified as insertions by our criteria (see Methods). That is, the retroelement was absent in Rhesus. The other 110 sites were examined more closely. Fifty-two of these cases appeared to be rearrangements or multi-copy regions in the Rhesus genome due to the existence of multiple Rhesus traces covering the region, some with and some without the retroelement. Three further cases with partial poor trace alignments were likely genomic rearrangements. The remaining 55 cases were subjected to more detailed analysis to confirm that the indel was a case of deletion in human or chimpanzee and not an insertion or other rearrangement. Multiple sequence alignments of the human, chimpanzee, and Rhesus sequences were done in each of the 55 cases (reproduced in Appendix A). Only one (# 23) resulted from poor sequence quality in the chimpanzee assembly. Another (#51) was a tandemly-duplicated L2 element. Four other cases (# 5, 13, 18, and 31) showed evidence of independent insertions in the same site or in sites only several base pairs apart. Independent insertions at the same site have been reported before (Conley et al. 2005). The remaining 49 cases appeared to be retroelement deletions. Twelve cases, six in humans and six in chimpanzees, were imprecise deletions, removing sequence from older retroelements such as L2 and MIR. A similar case of imprecise Alu deletion has been previously reported (Edwards and Gibbs 1992). In each case, our 12 imprecise 105 deletions had little or no similarity at the deletion breakpoints, suggesting a non-homologous deletion mechanism as an explanation for these events. Thirty-seven cases represented apparent precise deletion of previously retrotransposed sequence and all cases but one were Alu elements. The one anomaly (case #6) was a polyadenylated sequence flanked by apparent target site duplications. This is a fragment of a -340 bp sequence with -20 copies mutually -6-10% divergent in the human genome, suggesting possible earlier mobilization as a retrotransposable element. We found 36 cases of apparent precise deletions of Alu elements. The loss of the Alu was also associated with loss of one copy of the TSD, leaving behind the original, pre-integration site only. This observation raised the possibility that these deletions were mediated by recombination between the flanking identical regions. A possible example of precise Alu deletion on human chromosome 21 has been reported recently by Hedges et al (Hedges et al. 2004) but the authors considered Alu excision to be a remote possibility, instead favoring other explanations. Unfortunately, there is no coverage of this region in the chimpanzee scaffolds. Furthermore, recent PCR analysis of human-chimpanzee indels on chimpanzee chromosome 22 revealed two precisely deleted Alu elements; however, sequences and positions of these events were not given. These deletions resulted in loss of the Alu and deletion of one of the TSD copies, leading the authors to speculate that a homology-dependent recombination mechanism might be responsible for these deletions (Watanabe et al. 2004). We reasoned that under a null hypothesis of deletions mediated by non-homologous mechanisms, very few should be flanked by short identical segments. Instead, the majority of the 49 deletions (37 with flanking identical segments and 12 106 without) had identical regions of 10 bp or more. Compared to the null hypothesis, this association between deletion and flanking identical D N A was highly significant (p < le-100; Chi squared test). The skeptical reader could argue that we were only looking at deletions with breakpoints near retroelements, and therefore we would be more likely to find breakpoints located within TSDs, even with a non-homologous deletion mechanism. However, the likelihood of locating the breakpoints precisely at the same location within the TSD in the vast majority of the cases by random chance alone remains extremely small. Our findings strongly suggest that short, nonadjacent identical segments recombine, likely during double-strand break repair, to mediate deletion of these sequences. Consistent with this notion is the fact that at least 20-fold more deletions that involve Alus are actually internal to Alu elements and have occurred between the roughly 80-bp and 50-bp homologous regions internal to intact Alu elements (Figure 5.1 A; See Methods). These findings suggest that double strand D N A breaks internal to Alus are repaired using the internal Alu homologies, obviating use of the flanking TSDs as repair templates and thus retaining remnants of the Alu element. The proposed mechanism of double-strand break repair is illustrated in Figure 5.IB, which shows a specific non-Alu small deletion in chimpanzee. 107 A 740 X 242 X B 1. ACCGGCTGCTGTGGGGCA GATTTGCTTTCGGG 133333Y09Y3YD33331 3iYYYD9YW3033 ACCGGCTGCTGTGGGGCA TTTGCTTTCGGG I.33333Y09Y3YD3D3 31YYY03YW33D3 3. o o E-i O T T C G G G A C C G G C ^ ^ T o 4. ACCGGCTGCTTTCGGG I33333VD9YYY3333 Figure 5.1 Deletions due to DNA double strand break repair. A) Whole and partial Alu element deletions. A full-length Alu is shown in the middle and black arrows represent target site duplications. Shaded and white internal regions represent internal -70% identical regions. Deletions involving the 84 bp internal Alu homologies (shaded regions) were found 740 times in the human-chimpanzee alignments (top left). Alu internal deletions occurring between the other homologies (white regions) were found 242 times (top right). Precise deletion of entire Alu elements, likely involving the target site duplication (black arrows) was found in 36 cases (lower) in relatively repeat-free regions since human-chimpanzee divergence. B) A non-Alu deletion in chimpanzee at human chrl: 1448280-1448311. Precise deletions of Alu elements, internal deletions within Alus, and other deletions are explained by an error-prone homology-dependent repair mechanism, involving 1. a double-strand DNA break, 2. resection of DNA and exposure of 3' tails, 3. homology search, and 4. ligation. In this case, a 4-bp homology mediated a 16-bp deletion. 108 Several of the apparent deletions from chimpanzee corresponded in human to human-specific Alu families, such as AluYa5 and AluYb8. However, in each case the corresponding element in Rhesus monkey shared identical TSDs and was also an AluY. Two explanations can account for this observation: multiple independent insertions at the identical site, or recent gene conversion in human which converted an existing older AluY insertion into an apparent human-specific family. Although we cannot rule out independent insertions as an explanation in these cases, we believe gene conversion, reported previously to occur between Alu elements (Salem et al. 2003a), is more likely. It should be noted that both deletion in the chimpanzee lineage and gene conversion in the human lineage, rather than controverting one another, are dual lines of evidence suggesting elevated recombinational or double-strand D N A break repair activity in these loci in recent evolutionary time. We further noticed a relative paucity of precise deletions in human vs. chimpanzee (only 9/37 occurred in the human lineage). Without further study, it is unclear what this might mean. However, further B L A T alignments confirmed that, with the exception of two events (case #25, deleted in human, and case #43, deleted in chimpanzee), these events have all occurred in single-copy regions of the human and chimpanzee genomes. Furthermore, we used discontiguous megablast against the chimpanzee sequence trace database at NCBI to check for the possibility that some of the putative deletions in chimpanzee were a result of anomalous assembly, in which an Alu-containing trace at a locus was over-ruled by traces not containing the Alu. No such cases were found. By comparison, the numbers of random deletions between 200 and 500 bp long, discussed below, were more similar between human and chimpanzee (1011 and 916, respectively). 109 5.3.2 Analysis of random genomic deletion by illegitimate recombination To further investigate the genomic prevalence of deletions that might be mediated by short repeats during the last few million years of primate evolution, we examined all length differences of 200-500 bp (thus approximating the 300-bp size of Alu elements) between human and chimpanzee and looked for flanking repeats at the breakpoints. After eliminating cases of tandem duplications, insertions (including sequence having additional copies elsewhere in the human genome), indels within transposable elements, and deletions between homologous transposable elements (see Methods), 1927 indels remained, and we termed these random deletions. It should be noted that our method did not exclude genomic deletions having one or both breakpoints within repetitive sequence, as long as the repetitive sequence at the endpoints did not belong to homologous repeats. We found that the endpoints of 367, or 19.0% of 200-500 bp random deletions in the human and chimpanzee lineages, are associated with flanking identical repeats of at least 10 bp. To put this observation in the context of non-random sequence composition in primate genomes, we attempted to measure the background density of nonadjacent homologies 200-500 bp apart occurring in nonrepetitive human genome sequence. Therefore, repetitive sequence recognized by RepeatMasker (A.F.A. Smit & P. Green, unpublished data; and tandem repeats found by Tandem Repeats Finder 3.21 (Benson 1999) were excised from the genome. This left 1.58 Gbp, or 55.6%o of the human genome. A C++ program was constructed that computed alignments between all genomic positions 200 to 500 bp apart. From the banded alignments, the program directly calculated the length distribution of randomly-occurring identical segments flanking sequence tracts 200-500 bp long. We then extrapolated the 110 observed homology counts to compute the expected random homology occurrence in a complete genome. This method projected that 1.62 million random homologies of 10+ bp would exist 200-500 bp apart in the full size 2.84 Gbp human genome. The 376 random deletions that we observe with 10+ bp flanking repeats therefore account for 0.0226% of all such homologies available in the genome. This observation again fits well within the paradigm of deletion-prone homology-driven D N A double strand break repair, known as single-strand annealing (Karran 2000; Helleday 2003). In that model, D N A breakage results in binding of complexes that initiate peeling back of DNA, followed by a stochastic homology search in regions adjacent to the broken ends. In this type of D N A repair, many local homologies may be bypassed before fortuitous matching occurs. Exonucleases break down loose D N A ends, followed by ligation of the broken ends (Figure 5.IB). This mechanism accounts for deletion sizes over several orders of magnitude (data not shown), and for varying flanking repeat sizes (Figure 5.2). I l l 1600 14001 CD o c CD i _ zs o o O 400 200 0 • • O b s e r v e d I _ • Expected III I • • • • • • • • • • • -0 2 4 6 8 10 12 14 16 Flanking repeat size (bp) 18 Figure 5.2 Prevalence of direct repeats at deletion boundaries. 1927 random deletions 200-500 bp in length were observed in the UCSC chimpanzee scaffold alignments to the July 2003 human genome. Observed flanking repeat occurrence (black bars) and expected occurrence if these deletions occurred by nonhomologous end joining alone (grey bars) are displayed. Flanking repeats 7 bp in size and above are expected to occur in <1/1927 cases. As observed with Alu deletions, the observed association of random deletions with 10+ bp flanking repeats appeared much greater than would occur i f homology played no role. Indeed, the suggestion that nonadjacent homologies play a role in genomic deletions has also been made based on studies in plants, although no statistical analysis has been done (Devos et al. 2002; Ma and Bennetzen 2004). To statistically confirm a strong association between flanking repeats and deletion, our results were compared to what would be expected in a process of purely random breakage followed by blunt-end rejoining (Figure 5.2). We reasoned that, under the hypothesis of no association between homology at breakpoints and deletion occurrence, homology occurrence at breakpoints of 200-500 bp deletions should mirror that observed 200-500 bp apart in the nonrepetitive genome. Using the data described above without extrapolation, 0.903 million randomly-occurring homologies occur in the nonrepetitive 112 genome, wherein there exist 300 times as many, or 0.474 trillion position combinations 200-500 bp apart. Thus 10+ bp homologies occur randomly at a frequency of 1.9 x 10"6 of any two positions 200-500 bp apart. Therefore, i f homology plays no role in these deletions, we would expect much less than one occurrence of 10+ bp homology in our set of 1927 deletions (1927 * 1.9 x 10"6 = 0.0036 occurrences, precisely), compared to the observed 367 occurrences (P « 1 x 10"100; Chi-squared test). Furthermore, by plotting the observed number of deletions associated with different lengths of flanking identity, we found that flanking repeats as short as two base pairs were overrepresented in the data set (Figure 5.2). This strong association of short flanking identities with deletion further confirms that illegitimate recombination between such short sequences has played a highly significant role in sequence deletion during primate evolution. 5.3.3 Direct confirmation of Alu element deletions Finally, to confirm our findings, we chose 9 cases of AluS elements present in human but absent in the draft chimpanzee sequence to examine in more detail. These loci were chosen within and at varying distances from genes. To avoid regions of poor or anomalous alignments, we only investigated cases where the percentage identity between human and chimpanzee sequence surrounding the Alu is very high (>98%) and the Alu is a complete element with recognizable target site duplications (TSDs). Five of the cases (#14, 33, 42, 43, and 52; see Appendix A) were predicted to be deletions in chimpanzee, and as a control we selected four cases expected to be insertions in human (# C1-C4). The presence or absence of each of these Alus in a range of primate species was then determined using genomic PCR and the results summarized in Table 5.1. 113 Table 5.1 AluS indels assayed in primates by PCR and BLAST #1 Fam. Position2 TSD 3 H 4 C 4 C1 Sx 20:11512274 13 Y 6 N 6 C2 Sg 15:83819720 16 Y N C3 Sg 7:104197804 19 Y N C4 Sg 20:18254452 15 Y N 3:127318836 17 Y N 14 Sg 15) 33 Sx 42 Sq 43 Sx protein) G 4 O 4 Gi 4 B 4 R 5 Location/nearest genes N N N N N -354 kb 5' of BTBD3 (BTB/POZ domain containing-3) N N N N N In intron of AKAP13 (A-kinase anchor protein) N N I7 N N -17 kb 5' of MLL5 (Myeloid/lymphoid leukemia 5) N N N N N -9.7 kb 5' of ZNF133 (Kruppel Zn-finger protein) Y Y ? ? Y -63 kb 3' of KLF15 (Kruppel-like factor 12:48585272 16 Y N 16:69279114 16 Y N Y Y Y Y Y Y Y Y Y Y 16:74232245 17 Y Y/N° Y Y Y ? Y In intron of LOC348174 (secretory 1.3 kb 5' of FAIM2 (Fas apoptotic inhibitory molecule 2) 5.2 kb 3' of CYB5-M (cytochrome b5) 52 Sq 22:45658137 15 Y N Y ? Y ? Y In intron of C22orf4 (putative GTPase activator) 1 Case number. Cases Cn are controls, and others refer to case number in Supplementary information. 2 Chromosome and position in July 2003 Human Genome Browser ( 3 Size of Target Site Duplication (bp) 4 H- human; C-chimpanzee; G- gorilla; O- Orangutan; Gi- Gibbon; B- Baboon; assayed by PCR 5 R- Discontiguous MegaBLAST results from Rhesus monkey trace archive. 6 Y= Alu is present; N= Alu is absent (as determined by PCR or Discontiguous MegaBLAST); ?= primers did not amplify or product of unexpected size I = Independent Alu insertion in same region in Gibbon 8 Alu #43 is 'polymorphic' in all chimpanzees tested. Region is triplicated in human with all 3 having the Alu in human and one region lacking the Alu in chimpanzee. A B C D E F G H C G O G i B - H C G O G i B - H C G O G i B - H C G O G i B - H C G O G i B - H C G O G i B - 1 2 3 4 5 6 Figure 5.3 PCR and sequence evidence for precise Alu element deletion. A-F) cases C4,14,33,42, 52, 43 from Table 5.1; lanes are human (H), chimpanzee (C), gorilla (G), orangutan (O), gibbon (Gi), baboon (Ba), and no-template control (-) G) case 43, genomic PCR in 6 additional chimpanzees, labeled 1-6. 114 As expected, our four controls demonstrate AluS presence only in human and no other primate, consistent with insertion in the human lineage after divergence from chimpanzee (Table 5.1, Figure 5.3A). In accord with this finding is a study suggesting that some AluSx elements may still be active (Johanning et al. 2003). Therefore, some of the non-AluY differences between human and chimpanzee may reflect recent low levels of retrotranspositional activity of AluS elements. An alternative explanation is that young AluY elements inserted in these locations, followed by gene conversion templated by older AluS elements. We therefore more carefully examined these Alu sequences to look for nucleotide positions diagnostic of young AluY subfamilies (Batzer and Deininger 2002). Although we found no convincing evidence for partial gene conversion, this mechanism cannot be ruled out. Interestingly, in control #3, gibbon has an independent AluY insertion at this locus, offset by 4 bp (NCBI Accession no. AY953324). Independent parallel retroelement insertions at or near the same genomic site have been previously noted (Salem et al. 2003a; Conley et al. 2005). In the remaining five cases, PCR evidence confirms deletion in chimpanzee rather than lineage-specific insertion in human (Table 5.1). In four cases (#14, 33, 42, and 52), the Alu element was found to be uniformly present in 10 of 10 humans and absent in 10 of 10 chimpanzee D N A samples (data not shown). These four regions are apparently unique in the human genome with no evidence of segmental duplication. Insertion of these Alu elements could be verified by PCR in orangutan, which diverged from the higher apes 12-15 mya (Glazko and Nei 2003), or in even more distantly related primates (Figure 5.3B-E). (For case #14 in gibbon, the PCR product was of unexpected size, Figure 5.3E, suggesting rearrangement or other insertions in the region.) Given these long periods of time, it is unlikely that these loci reflect lineage sorting of ancestral 115 polymorphisms, proposed previously to explain unexpected Alu presence/absence relationships in the great apes (Salem et al. 2003b; Hedges et al. 2004). Rather, these results suggest that pre-existing fixed Alu elements have been deleted in the chimpanzee lineage. To verify that the loci in other primates contain the same Alu insertion, we sequenced the region in gorilla for cases #33 and 52 (NCBI Accession nos. AY953323 and AY953322) and compared to the human, chimpanzee, and Rhesus macaque genomic sequences from the databases (Figure 5.4A,B). In both cases, the gorilla and Rhesus loci are occupied by the same ancestral Alu as in human with the same target site duplication (TSD). Moreover, the sequence in chimpanzee has the expected structure of the pre-integration locus with only one copy of the TSD generated upon Alu insertion. A human c h i m p g o r i l l a r h e s u s TSD TSD GGGTGGGAT GGGTGGGAT GGGTGGGAT GGATGGGAT A A A G A C T T T G A T A A T T A A A G A C T T T G A T A A T T A A A G A C T T T G A T A A T T A A A G A C T T T G A T A A T T a g g c c - A L U - a a a a A A A G A C T T T G A T A A T T a g g c c a g g c c - A L U -- A L U -a a a a a a a a A A A G A C T T T G A T A A T T A A A G G C T T — A T A A T T T G T C T G C C T T G T C T G C C T T G T C T G C C T T G T C T G C C C B human c h i m p g o r i l l a r h e s u s c human1 human2 human 3 c h i m p 1 c h i m p 2 r h e s u s GACGGTAAA GAGGGTAAA GAGGGTAAA GAGGGTAAA G A A A T G C C C C C T C T C G A A A T G T C C C C T C T C G A A A T G C C C C C T C T C G A A A T G C C C C C T C T C g g c c - A L U - a a a a G A A A T G C C C C C T C T C g g c c g g c c - A L U -- A L U -a a a g a a a a G A A A T G C C C C C T C T C G A A A T G T C C C C T C T C A C A A A A C T G A C A A A A T T G A C A A A A C T G A C A A A A T T G C C C T T G T T T C A C T T G T T T C A C T T G T T T C C C T T G T T T C C C T G G T T T C C C T T G T T T AAGAAGAGGGAGGG AAGAAGAGGGAGGG AAGAAGAGGGAGGG AAGAAGAGGGAGGG AAGAAGAGGGAGGG AAGAAGAGGGAGGG g g c t - A L U - a a a a g g c t - A L U - a a a a g g c t - A L U - a a a a AAGAAGAGGGAGGG AAGAAGAGGGAGGG AAGAAGAGGGAGGG g g c t - A L U - a a a a g g c t - A L U - a a a g AGGAAGAGGGAGGG AAGAAGAGGGAGGG GGCGGGGTCAGCT GGCGGGGTCAGCT GGCGGGGTCAGCT GGCGGGGTCAGCT GGCGGGGTCAGCT , GGCGGGGTTAGCT Figure 5.4 Sequence evidence for precise Alu element deletion. A,B) cases 33 & 52, sequenced in gorilla and compared to the database sequences of human, chimpanzee, and Rhesus macaque C) case 43, showing available human, chimpanzee, and Rhesus loci. Target site duplications are boxed. The final case (#43) is more complex in that chimpanzee appears to have both occupied and unoccupied alleles or loci (Figure 5.3F). This pattern was seen in D N A from 6 of 6 additional chimpanzees tested (Figure 5.3G), suggesting that it does not reflect allelic polymorphism. Indeed, database analysis revealed that this locus is part of 116 complex segmental duplications that resulted in three copies in the human genome, all of which have the Alu insertion. The draft chimpanzee sequence has two copies, one of which lacks the Alu insertion. We cannot determine i f a third copy exists in chimpanzee because of gaps and poor sequence coverage in these regions. A n alignment of the three human and two chimpanzee sequences, as well as one Rhesus sequence is depicted in Figure 5.4C and shows that the chimpanzee locus without the Alu has the expected structure of a pre-integration allele. We confirmed the database entries by sequencing the two loci in chimpanzee (NCBI Accession nos. AY953325 and AY953326). The most probable explanation for this finding is that the Alu integrated prior to duplication of the region followed by loss of the Alu in one chimpanzee copy. 5.4 Concluding remarks In summary, our analysis strongly suggests an important role for short nonadjacent segments of D N A identity in genomic deletions. In rare cases, even retroelement insertions deeply fixed in the primate lineage can apparently be precisely excised from the genome in a manner involving the flanking TSDs, leaving behind no footprint of their insertion. We believe that illegitimate recombination between short identical stretches of DNA, likely involving a D N A double-strand break repair mechanism, is the most likely and simplest molecular mechanism to explain the findings reported here. This conclusion is supported by the fact that a large fraction of non-TE associated deletions distinguishing human and chimpanzee have short repeats at the breakpoints. Furthermore, this study provides new insights into genomic attenuation and contradicts a rigid view that all insertions of retroelements represent unidirectional events. On the other hand, this study demonstrates that, for A l u elements in particular, homoplasy freedom is a mostly valid assumption and implicates internal homologous regions as preventing wholesale deletion 117 of Alus. Finally, an aspect of Alu biology that has provoked interest is the slight preferential localization of younger elements in AT-rich regions but higher density of older elements in more GC-rich D N A (International Human Genome Sequencing Consortium 2001). Several theories have been proposed to explain the differences in Alu distributions with element age (Schmid 1998; Brookfield 2001; Pavlicek et al. 2001; Medstrand et al. 2002; Jurka 2004). While our findings indicate that precise deletion of Alu elements makes reversal of retroelement insertions possible, the phenomenon is nevertheless quite rare (-0.5% of length polymorphisms) and is likely insufficient to explain the shifts in Alu distribution. However, ectopic illegitimate recombination not involving TSDs may help to explain overall Alu sequence loss and distribution patterns. 118 Chapter 6: Summary and conclusions 119 6.1 Summary The purpose of this thesis work was to use global analyses of populations of repeated sequences of various kinds in mammalian genomes to understand the interactions of these sequences and their host genomes. The methods developed in this pursuit were almost exclusively computational and involved analysis of sequenced human, chimpanzee, and mouse genomes and related sequence data. Trends identified in our analyses have provided insight into the global effects of transposable elements and their impact on the host. Below I briefly discuss several considerations arising out of this work. 6.2 Initial and long-term genomic localization of mobile elements are related in complex ways Appropriate normalization of the currently observed distributions of repetitive elements allows comparison of the distributions of elements with widely varying total population sizes. While most element types seem simply to be lost from high-GC regions over time, the Alu distribution is particularly intriguing, in that very young and very old Alus seem to have less of a high-GC sequence composition preference, while Alus of intermediate ages seem to be strongly clustered in regions of high-GC content, which, in many cases, coincide with gene-rich regions. Several explanations have been advanced that may account for these observations, each perhaps explaining some part of the nascence of the observed mobile element distributions. Our own work pointed to a role for recombination in shaping the distributions of Alu elements (Chapter 2). However, a complete understanding of the localization of different retroelements in regions of varying sequence composition requires knowledge of all processes taking place at and after the time of insertion. The 120 recent discoveries that transcripts, particularly those of exogenous viruses such as HIV, can be tethered in genie regions resulting in an altered propensity to insert there (Ciuffi et al. 2005; Lewinski and Bushman 2005) suggests that a similar mechanism may have accounted for the Alu accumulation in GC-rich regions. This theory is particularly pleasing in that it could explain the differential GC-content localization of the different Alu families based on their consensus sequence alone, without invoking any functional role or any more significant interactions with the genome. Furthermore, the recent discovery of base pair preferences in the vicinity of exogenous retroviral insertion sites (Holman and Coffin 2005) further suggests binding by tethering factors. Not least, differences in insertion patterns relative to genes for L I , SVA, and A l u retroelements, all of which are presumed to insert using LI-encoded machinery, strongly suggest the presence of auxiliary factors influencing the localization of these elements. 6.3 Some TEs interact strongly with genes, leading to population biases in regions surrounding genes Although the localization of insertions of mobile elements is apparently determined, at least in part, by the sequence composition of the region, a separate, gene-specific interaction may also be measured. It must be noted that, given the strong association between high-GC content and high gene density, some of the apparent genomic sequence composition effect on TE localization may be due to the presence of genes. In any case, mapping of TEs with respect to genes and comparison of this mapping with that expected by consideration of sequence composition alone allowed a conservative assessment of the effect of genes on TE localization (Chapter 2). In short, TEs whose life cycle involves transcription by the pol-II machinery, which therefore contain internal active pol-II transcriptional signals in their sequence, seem to be at least partially disallowed from 121 entry into pol-II transcribed regions, likely due to pathogenicity upon insertion there. This has been suggested by others (Smit 1999). However, disallowance of TEs in the same transcriptional direction as genes extends upstream and downstream of genes as well, especially for LTR-containing elements (Chapter 2), suggesting that the transcriptional signals provided by these elements are detrimental at some distance from genes. The fact that pol-II signal-containing TEs are not totally excluded from transcribed regions raises several interesting questions. If pol-II driven TEs are so pathogenic, why have they been allowed to remain at some level in transcribed regions? Are they disabled in some way? To what extent, i f any, does methylation silencing of TE pol-II promoters affect the permissiveness of genie regions for insertion of these elements? Do they have weaker promoters or polyadenylation signals? Are there adjacent cellular sequences that override these dangerous motifs in some way? Are there perhaps binding sites for tethering proteins that help keep the pol-II holoenzyme on track in spite of these polyadenylation signals? These and other questions suggest a fruitful avenue for further research. For example, it might be interesting to search for association between multi-species conserved sequences, which have recently been shown to occur at higher density within long introns (Sironi et al. 2005a; Sironi et al. 2005b), and sense-oriented pol-II driven TEs found in genie regions. 6.4 Many gene UTRs are associated with TE-derived sequence Analysis of transcripts revealed that 27.4% of human genes have permitted inclusion of TE sequence in the UTRs of one or more of their transcripts (Chapter 3). The corresponding figure for mouse is 18.4%. This lower figure may reflect the higher mutation rate in the mouse lineage, by which repetitive sequence becomes undetectable 122 by alignment methods. Indeed, mutually aligning genomic regions for which an older repeat is found in humans often have no annotated repeat in mouse, reflecting an inability of current alignment methods to find these repeats in mouse. In addition, high-copy repetitive sequence has, in general, been less well studied in the mouse lineage and the lower detected genomic coverage by repeats in rodent genomes is a reflection of this fact (Mouse Genome Sequencing Consortium 2002; Baillie et al. 2004). A synthesis of the mapping data we have in both humans and mouse results in a perhaps-unsurprisingly consistent picture of both systems. In both human and mouse, TEs appear to affect expression of many genes through donation of transcriptional regulatory signals. Furthermore, recently expanded gene classes, such as those involved in immunity or response to external stimuli, have transcripts enriched in TEs, whereas TEs are excluded from mRNAs of highly conserved genes with basic functions in development or metabolism. These results could support one of two views. On one hand, one might argue that TEs have played a significant role in the diversification and evolution of mammalian genes. On the other hand, a more neutralist conclusion might be that permissive genes are so because their product is less dosage-critical, and therefore interference with expression due to TE donation of signals or sequence is less likely to ill-affect such genes. In this regard, it would be interesting to study inclusion of TE sequence in transcripts in the context of variations in expression level. One might expect that genes whose expression level is critical and conserved across species would most strongly exclude TEs. A first attempt to study this might entail compilation of a list of haploinsufficient genes followed by assessment of TE content in their transcripts. 6.5 Short repeated sequences are involved in genomic deletions Insertion of transposable elements is a major cause of genomic expansion in eukaryotes. 123 Less is understood, however, about mechanisms underlying contraction of genomes. A combination of global bioinformatic analyses and PCR-based approaches showed that retroelements can, in rare cases, be precisely deleted from primate genomes, most likely via recombination between 10-20 bp TSDs flanking the retroelement (Chapter 5). The deleted loci are indistinguishable from pre-integration sites, effectively reversing the insertion. It is estimated that 0.5 to 1% of apparent retroelement insertions distinguishing humans and chimpanzees actually represent deletions. Furthermore, 19% of genomic deletions of 200-500 bp that have occurred since the human-chimpanzee divergence are associated with flanking identical repeats of at least 10 bp. A large number of deletions internal to Alu elements are also flanked by similar sequence. These results suggest that illegitimate recombination between short direct repeats has played, and likely continues to play, a significant role in human genomic deletion processes and is likely implicated in D N A deletion syndromes such as cancer. In short, while this study lends support to the view that insertions of retroelements are mostly irreversible, it is the first to conclusively demonstrate precise reversion of these events and estimate the rate of precise deletion of these elements. The data presented also suggested that the same mechanism is responsible for a large number of random genomic deletions. In addition to the insights it provided, our study of short direct repeats and their role in deletion processes suggests further questions. Perhaps we can learn more about the frequency of error-prone modes of operation of ideally error-free D N A DSB repair pathways. To answer this question, one might perform further study of putative deletions of all sizes, using other primate genomes to determine the ancestral state of indels. This approach would help to elucidate in further detail the contributions of the various D N A DSB repair mechanisms to genomic sequence change. Such insights can help us 124 understand the etiologies of cancer and similar diseases caused by D N A breakage and repair. 6.6 Conclusions Repeated sequences, primarily TEs, make up a large fraction of mammalian genomes. Bioinformatic analysis of genomic data is a uniquely powerful technique that has allowed us to conduct global genomic analyses of repeats and address their involvement in genomic-scale phenomena. The theme that has emerged repeatedly is the familiar one where the survival of the organism is the ultimate determinant of whether sequence change is accepted or not. Within this paradigm, apparently selfish sequence, such as that of apparently viral origin, may be co-opted by a genome to perform a useful function. However, it remains subservient to the needs of the organism, only rarely persisting when its overall impact is negative, and then only if the negative impact is slight. In rare cases, positive effect has been argued with convincing evidence, such as in the case of salivary expression of a digestive enzyme under the control of an enhancer of viral origin (Ting et al. 1992). As more detailed genomic analyses are done of insertions and deletions and genes affected by such events, it may be expected that more of these events will come to light. Especially interesting in this regard is the recent availability of the chimpanzee genome and its alignment with the human genome. Availability of more sequenced genomes promises to shed additional light on the role of repetitive D N A of all kinds in making the broad array of organisms what they are. Although their global nature makes bioinformatic analyses powerful, it is also limiting. Genome-wide analyses, though they survey all genes, cannot address every factor governing each individual case. This is largely because many influences on gene expression, for example chromatin remodeling and R N A interference to name just two, 125 though characterized on some level for individual genes, are at present far from being well-enough understood in terms of their regulation and their regulatory effect on other genes to apply that knowledge on a genomic scale. It is exciting to think that, as more data on the various phenomena become available, we may gain sufficient understanding to map such information to genomes and conduct global analyses of them. This and an increasing trove of sequencing and phenotypic data in the public databases promise to provide grist for bioinformatic analyses addressing more and more sophisticated biological questions as time progresses. A t no time, however, must the researcher lose sight of the critical importance of complementation of bioinformatic studies by wet laboratory approaches. Rather, bioinformatics and the wet laboratory are envisioned as partners in an iterative process, in which the wet lab provides fundamental understandings which are then used in global bioinformatic analyses. The goal of those analyses is to synthesize diverse data into a more systems-level picture of biology, offering a whole new round of hypotheses amenable to testing in wet-lab environments. 126 References Adams, M.D. , S.E. Celniker, R A . Holt, C A . Evans, J.D. Gocayne, P.G. Amanatides, S.E. Scherer, P.W. L i , R .A. Hoskins, R.F. Galle et al. 2000. The genome sequence of Drosophila melanogaster. Science 287: 2185-2195. Altschul, S.F., W. Gish, W. Miller, E.W. Myers, and D.J. Lipman. 1990. Basic local alignment search tool. J Mol Biol 215: 403-410. Aparicio, S., J. Chapman, E. Stupka, N . Putnam, J.M. Chia, P. Dehal, A . Christoffels, S. Rash, S. Hoon, A . Smit et al. 2002. Whole-genome shotgun assembly and analysis of the genome of Fugu rubripes. Science 297: 1301-1310. Athanikar, J.N., R . M . Badge, and J.V. Moran. 2004. A YY1-binding site is required for accurate human LINE-1 transcription initiation. Nucleic Acids Res 32: 3846-3855. Baillie, G.J., L .N . van de Lagemaat, C. Baust, and D.L. Mager. 2004. Multiple groups of endogenous betaretroviruses in mice, rats, and other mammals. J Virol 78: 5784-5798. Bannert, N . and R. Kurth. 2004. Retroelements and the human genome: new perspectives on an old relation. Proc Natl Acad Sci USA 101 Suppl 2: 14572-14579. Bao, Z. and S.R. Eddy. 2002. Automated de novo identification of repeat sequence families in sequenced genomes. Genome Res 12: 1269-1276. Barr, S.D., J. Leipzig, P. Shinn, J.R. Ecker, and F.D. Bushman. 2005. Integration targeting by avian sarcoma-leukosis virus and human immunodeficiency virus in the chicken genome. J Virol 79: 12035-12044. Batzer, M A . and P.L. Deininger. 2002. Alu repeats and human genomic diversity. Nat Rev Genet 3: 370-379. Baust, C , G.J. Baillie, and D.L. Mager. 2002. Insertional polymorphisms of ETn retrotransposons include a disruption of the wiz gene in C57BL/6 mice. Mamm Genome 13: 423-428. Baust, C , W. Seifarth, H . Germaier, R. Hehlmann, and C. Leib-Mosch. 2000. HERV-K-T47D-Related long terminal repeats mediate polyadenylation of cellular transcripts. Genomics 66: 98-103. Bedell, J.A., I. Korf, and W. Gish. 2000. MaskerAid: a performance enhancement to RepeatMasker. Bioinformatics 16: 1040-1041. Belshaw, R., A . L . Dawson, J. Woolven-Allen, J. Redding, A. Burt, and M . Tristem. 2005. Genomewide screening reveals high levels of insertional polymorphism in the human endogenous retrovirus family HERV-K(HML2) : implications for present-day activity. J Virol 79: 12507-12514. Bennett, E.A., L .E . Coleman, C. Tsui, W.S. Pittard, and S.E. Devine. 2004. Natural genetic variation caused by transposable elements in humans. Genetics 168: 933-951. Benson, G. 1999. Tandem repeats finder: a program to analyze D N A sequences. Nucleic Acids Res 27: 573-580. Biemont, C , A . Tsitrone, C. Vieira, and C. Hoogland. 1997. Transposable element distribution in Drosophila. Genetics 147: 1997-1999. Blond, J.L., F. Beseme, L. Duret, O. Bouton, F. Bedin, H. Perron, B. Mandrand, and F. Mallet. 1999. Molecular characterization and placental expression of HERV-W, a 127 new human endogenous retrovirus family. J Virol 73: 1175-1185. Boeke, J.D. and J.P. Stoye. 1997. Retrotransposons, Endogenous Retroviruses, and the Evolution of Retroelements. In Retroviruses (eds. J .M. Coffin S.H. Hughes, and H.E. Varmus), pp. 343-436. Cold Spring Harbor Laboratory Press, Plainview, New York, USA. Brady, H.J., J.C. Sowden, M . Edwards, N . Lowe, and P.H. Butterworth. 1989. Multiple GF-1 binding sites flank the erythroid specific transcription unit of the human carbonic anhydrase I gene. FEBS Lett 257: 451-456. Brandt, V . L . and D.B. Roth. 2004. V(D)J recombination: how to tame a transposase. Immunol Rev 200: 249-260. Britten, R.J. 1997. Mobile elements inserted in the distant past have taken on important functions. Gene 205: 177-182. Britten, R.J., L . Rowen, J. Williams, and R.A. Cameron. 2003. Majority of divergence between closely related D N A samples is due to indels. Proc Natl Acad Sci USA 100: 4661-4665. Brookfield, J.F. 2001. Selection on Alu sequences? Curr Biol 11: R900-901. Brosius, J. 1999. Genomes were forged by massive bombardments with retroelements and retrosequences. Genetica 107: 209-238. Bushman, F., M . Lewinski, A . Ciuffi, S. Barr, J. Leipzig, S. Hannenhalli, and C. Hoffmann. 2005. Genome-wide analysis of retroviral D N A integration. Nat Rev Microbiol 3: 848-858. Bushman, F.D. 2003. Targeting survival: integration site selection by retroviruses and LTR-retrotransposons. Cell 115: 135-138. Callinan, P.A., J. Wang, S.W. Herke, R.K. Garber, P. Liang, and M . A . Batzer. 2005. Alu retrotransposition-mediated deletion. J Mol Biol 348: 791-800. Cameron, H.S., D. Szczepaniak, and B.W. Weston. 1995. Expression of human chromosome 19p alpha(l,3)-fucosyltransferase genes in normal tissues. Alternative splicing, polyadenylation, and isoforms. J Biol Chem 270: 20112-20122. Carcedo, M.T., J .M. Iglesias, P. Bances, R.O. Morgan, and M.P. Fernandez. 2001. Functional analysis of the human annexin A5 gene promoter: a downstream D N A element and an upstream long terminal repeat regulate transcription. Biochem J 356: 571-579. Carlton, V.E. , B.Z. Harris, E.G. Puffenberger, A . K . Batta, A.S. Knisely, D.L. Robinson, K . A . Strauss, B.L . Shneider, W.A. Lim, G. Salen et al. 2003. Complex inheritance of familial hypercholanemia with associated mutations in TJP2 and B A A T . Nat Genet 34: 91-96. Carroll, M.L . , A . M . Roy-Engel, S.V. Nguyen, A . H . Salem, E. Vogel, B. Vincent, J. Myers, Z. Ahmad, L . Nguyen, M . Sammarco et al. 2001. Large-scale analysis of the Alu Ya5 and Yb8 subfamilies and their contribution to human genomic diversity. J Mol Biol 311: 17-40. Charlesworth, B. and D. Charlesworth. 1983. The population dynamics of transposable elements. Genet Res 42: 1-27. Charlesworth, B. and C H . Langley. 1991. Population genetics of transposable elements in Drosophila. In Evolution at the molecular level (eds. R.K. Selander A . G . Clark, and T.S. Whittam), pp. 150-176. Sinauer Associates, Sunderland, M A , USA. Charlesworth, B., C H . Langley, and P.D. Sniegowski. 1997. Transposable element distributions in Drosophila. Genetics 147: 1993-1995. 128 Chen, J.M., P.D. Stenson, D.N. Cooper, and C. Ferec. 2005. A systematic analysis of LINE-1 endonuclease-dependent retrotranspositional events causing human genetic disease. Hum Genet 117: 411-427. Ciuffi, A. , M . Llano, E. Poeschla, C. Hoffmann, J. Leipzig, P. Shinn, J.R. Ecker, and F. Bushman. 2005. A role for LEDGF/p75 in targeting HIV D N A integration. Nat Med 11: 1287-1289. Clamp, M . , J. Cuff, S.M. Searle, and G.J. Barton. 2004. The Jalview Java alignment editor. Bioinformatics 20: 426-427. Conley, M.E. , J.D. Partain, S.M. Norland, S.A. Shurtleff, and H.H. Kazazian, Jr. 2005. Two independent retrotransposon insertions at the same site within the coding region of BTK. Hum Mutat 25: 324-325. Cordonnier, A. , J.F. Casella, and T. Heidmann. 1995. Isolation of novel human endogenous retrovirus-like elements with foamy virus-related pol sequence. J Virol 69: 5890-5897. Costas, J. and H . Naveira. 2000. Evolutionary history of the human endogenous retrovirus family ERV9. Mol Biol Evol 17: 320-330. Csoka, A .B . , G.I. Frost, and R. Stern. 2001. The six hyaluronidase-like genes in the human and mouse genomes. Matrix Biol 20: 499-508. Cutter, A.D. , J .M. Good, C T . Pappas, M.A. Saunders, D . M . Starrett, and T.J. Wheeler. 2005. Transposable element orientation bias in the Drosophila melanogaster genome. J Mol Evol 61: 733-741. Deininger, P.L. and M . A . Batzer. 1999. Alu repeats and human disease. Mol Genet Metab 67: 183-193. Deininger, P.L. and M . A . Batzer. 2002. Mammalian retroelements. Genome Res 12: 1455-1465. Devos, K . M . , J.K. Brown, and J.L. Bennetzen. 2002. Genome size reduction through illegitimate recombination counteracts genome expansion in Arabidopsis. Genome Res 12: 1075-1079. Dewannieux, M . , C. Esnault, and T. Heidmann. 2003. LINE-mediated retrotransposition of marked Alu sequences. Nat Genet 35: 41-48. Dewannieux, M . and T. Heidmann. 2005. LI-mediated retrotransposition of murine B l and B2 SINEs recapitulated in cultured cells. J Mol Biol 349: 241-247. Di Cristofano, A. , M . Strazullo, L. Longo, and G. La Mantia. 1995. Characterization and genomic mapping of the ZNF80 locus: expression of this zinc-finger gene is driven by a solitary LTR of ERV9 endogenous retroviral family. Nucleic Acids Res 23: 2823-2830. Di Franco, C , A . Terrinoni, P. Dimitri, andN. Junakovic. 1997. Intragenomic distribution and stability of transposable elements in euchromatin and heterochromatin of Drosophila melanogaster: elements with inverted repeats Bari 1, hobo, and pogo. J Mol Evol 45: 247-252. Doolittle, W.F. and C. Sapienza. 1980. Selfish genes, the phenotype paradigm and genome evolution. Nature 284: 601-603. Dunbar, C E . 2005. Stem cell gene transfer: insights into integration and hematopoiesis from primate genetic marking studies. Ann N Y Acad Sci 1044: 178-182. Dunn, C.A., P. Medstrand, and D.L. Mager. 2003. An endogenous retroviral long terminal repeat is the dominant promoter for human betal,3-galactosyltransferase 5 in the colon. Proc Natl Acad Sci USA 100: 12841-12846. Dunn, C.A., L . N . van de Lagemaat, G.J. Baillie, and D.L. Mager. 2005. Endogenous 129 retrovirus long terminal repeats as ready-to-use mobile promoters: The case of primate beta3GAL-T5. Gene 364: 2-12. Edwards, M.C. and R.A. Gibbs. 1992. A human dimorphism resulting from loss of an Alu. Genomics 14: 590-597. Elliott, B., C. Richardson, and M . Jasin. 2005. Chromosomal translocation mechanisms at intronic alu elements in mammalian cells. Mol Cell 17: 885-894. Esnault, C , J. Maestre, and T. Heidmann. 2000. Human LINE retrotransposons generate processed pseudogenes. Nat Genet 24: 363-367. Friedrich, G. and P. Soriano. 1991. Promoter traps in embryonic stem cells: a genetic screen to identify and mutate developmental genes in mice. Genes Dev 5: 1513-1523. Fullerton, S.M., A . Bernardo Carvalho, and A . G . Clark. 2001. Local rates of recombination are positively correlated with GC content in the human genome. Mol Biol Evol 18: 1139-1142. Furano, A . V . 2000. The biological properties and evolutionary dynamics of mammalian LINE-1 retrotransposons. Prog Nucleic Acid Res Mol Biol 64: 255-294. Gibbons, R., L.J. Dugaiczyk, T. Girke, B. Duistermars, R. Zielinski, and A . Dugaiczyk. 2004. Distinguishing humans from great apes with AluYb8 repeats. J Mol Biol 339: 721-729. Gifford, R. and M . Tristem. 2003. The evolution, distribution and diversity of endogenous retroviruses. Virus Genes 26: 291-315. Gilbert, N . , S. Lutz-Prigge, and J.V. Moran. 2002. Genomic deletions created upon LINE-1 retrotransposition. Cell 110: 315-325. Glazko, G.V. and M . Nei. 2003. Estimation of divergence times for major lineages of primate species. Mol Biol Evol 20: 424-434. Goodchild, N.L . , D A . Wilkinson, and D.L. Mager. 1993. Recent evolutionary expansion of a subfamily of R T V L - H human endogenous retrovirus-like elements. Virology 196: 778-788. Goodman, M . , C A . Porter, J. Czelusniak, S.L. Page, H. Schneider, J. Shoshani, G. Gunnell, and C P . Groves. 1998. Toward a phylogenetic classification of Primates based on D N A evidence complemented by fossil evidence. Mol Phylogenet Evol 9: 585-598. Graves, J.A. 1995. The origin and function of the mammalian Y chromosome and Y -borne genes—an evolving understanding. Bioessays 17: 311-320. Greally, J .M. 2002. Short interspersed transposable elements (SINEs) are excluded from imprinted regions in the human genome. Proc Natl Acad Sci USA 99: 327-332. Gregory, T.R. 2001. Coincidence, coevolution, or causation? D N A content, cell size, and the C-value enigma. Biol Rev Camb Philos Soc 76: 65-101. Hacein-Bey-Abina, S., C. Von Kalle, M . Schmidt, M.P. McCormack, N . Wulffraat, P. Leboulch, A. Lim, C.S. Osborne, R. Pawliuk, E. Morillon et al. 2003. L M 0 2 -associated clonal T cell proliferation in two patients after gene therapy for SCID-X I . Science 302: 415-419. Hamdi, H. , H . Nishio, R. Zielinski, and A . Dugaiczyk. 1999. Origin and phylogenetic distribution of Alu D N A repeats: irreversible events in the evolution of primates. J Mol Biol 289: 861-871. Hamdi, H.K., H . Nishio, J. Tavis, R. Zielinski, and A . Dugaiczyk. 2000. Alu-mediated phylogenetic novelties in gene regulation and development. J Mol Biol 299: 931-939. 130 Han, J.S. and J.D. Boeke. 2004. A highly active synthetic mammalian retrotransposon. Nature 429: 314-318. Han, J.S., S.T. Szak, and J.D. Boeke. 2004. Transcriptional disruption by the LI retrotransposon and implications for mammalian transcriptomes. Nature 429: 268-274. Harada, F., N . Tsukada, and N . Kato. 1987. Isolation of three kinds of human endogenous retrovirus-like sequences using tRNA(Pro) as a probe. Nucleic Acids Res 15: 9153-9162. Hassoun, H. , T.L. Coetzer, J.N. Vassiliadis, K .E . Sahr, G.J. Maalouf, S.T. Saad, L. Catanzariti, and J. Palek. 1994. A novel mobile element inserted in the alpha spectrin gene: spectrin dayton. A truncated alpha spectrin associated with hereditary elliptocytosis. J Clin Invest 94: 643-648. Hedges, D.J., P A . Callinan, R. Cordaux, J. Xing, E. Barnes, and M A . Batzer. 2004. Differential alu mobilization and polymorphism among the human and chimpanzee lineages. Genome Res 14: 1068-1075. Helleday, T. 2003. Pathways for mitotic homologous recombination in mammalian cells. Mutat Res 532: 103-115. Higgins, D.G., J.D. Thompson, and T.J. Gibson. 1996. Using C L U S T A L for multiple sequence alignments. Methods Enzymol 266: 383-402. Holman, A . G . and J .M. Coffin. 2005. Symmetrical base preferences surrounding HIV-1, avian sarcoma/leukosis virus, and murine leukemia virus integration sites. Proc Natl Acad Sci USA 102: 6103-6107. Holmes, I. 2002. Transcendent elements: whole-genome transposon screens and open evolutionary questions. Genome Res 12: 1152-1155. Hurst, L.D. 2002. The Ka/Ks ratio: diagnosing the form of sequence evolution. Trends Genet 18: 486. International Human Genome Sequencing Consortium. 2001. Initial sequencing and analysis of the human genome. Nature 409: 860-921. Jern, P., G.O. Sperber, G. Ahlsen, and J. Blomberg. 2005. Sequence variability, gene structure, and expression of full-length human endogenous retrovirus H. J Virol 79: 6325-6337. Jern, P., G.O. Sperber, and J. Blomberg. 2004. Definition and variation of human endogenous retrovirus H . Virology 327: 93-110. Jiang, N . , Z. Bao, X . Zhang, S.R. Eddy, and S.R. Wessler. 2004. Pack-MULE transposable elements mediate gene evolution in plants. Nature 431: 569-573. Jiang, N . , Z. Bao, X . Zhang, H . Hirochika, S.R. Eddy, S.R. McCouch, and S.R. Wessler. 2003. An active D N A transposon family in rice. Nature 421: 163-167. Johanning, K. , C A . Stevenson, O.O. Oyeniran, Y . M . Gozal, A . M . Roy-Engel, J. Jurka, and P.L. Deininger. 2003. Potential for retroposition by old A l u subfamilies. J Mol Evol 56: 658-664. Johnson, R.D. and M . Jasin. 2000. Sister chromatid gene conversion is a prominent double-strand break repair pathway in mammalian cells. Embo J19: 3398-3407. Jordan, I.K., L B . Rogozin, G.V. Glazko, and E.V. Koonin. 2003. Origin of a substantial fraction of human regulatory sequences from transposable elements. Trends Genet 19: 68-72. Junakovic, N . , A . Terrinoni, C. Di Franco, C. Vieira, and C. Loevenbruck. 1998. Accumulation of transposable elements in the heterochromatin and on the Y chromosome of Drosophila simulans and Drosophila melanogaster. J Mol Evol 131 46: 661-668. Jurka, J. 1997. Sequence patterns indicate an enzymatic involvement in integration of mammalian retroposons. Proc Natl Acad Sci U S A 94: 1872-1877. Jurka, J. 2000. Repbase update: a database and an electronic journal of repetitive elements. Trends Genet 16: 418-420. Jurka, J. 2004. Evolutionary impact of human A l u repetitive elements. Curr Opin Genet Dev 14: 603-608. Kamat, A . , M . M . Hinshelwood, B . A . Murry, and C.R. Mendelson. 2002. Mechanisms in tissue-specific regulation of estrogen biosynthesis in humans. Trends Endocrinol Metab 13: 122-128. Kaplan, N . L . and J.F. Brookfield. 1983. The effect of homozygosity of selective differences between sites of transposable elements. Theor Popul Biol 23: 273-280. Karolchik, D . , R. Baertsch, M . Diekhans, T.S. Furey, A . Hinrichs, Y . T . L u , K . M . Roskin, M . Schwartz, C W . Sugnet, D.J . Thomas et al. 2003. The U C S C Genome Browser Database. Nucleic Acids Res 31: 51-54. Karran, P. 2000. D N A double strand break repair in mammalian cells. Curr Opin Genet £>evl0 : 144-150. Kashkush, K . , M . Feldman, and A . A . Levy. 2003. Transcriptional activation of retrotransposons alters the expression of adjacent genes in wheat. Nat Genet 33: 102-106. Kazazian, H . H . , Jr. 2004. Mobi le elements: drivers of genome evolution. Science 303: 1626-1632. Kazazian, H . H . , Jr., C . Wong, H . Youssoufian, A . F . Scott, D . G . Phillips, and S.E. Antonarakis. 1988. Haemophilia A resulting from de novo insertion of L I sequences represents a novel mechanism for mutation in man. Nature 332: 164-166. Kent, W.J . 2002. BLAT—the B L A S T - l i k e alignment tool. Genome Res 12: 656-664. Kent, W.J . , C W . Sugnet, T.S. Furey, K . M . Roskin, T . H . Pringle, A . M . Zahler, and D. Haussler. 2002. The human genome browser at U C S C . Genome Res 12: 996-1006. Kidwel l , M . G . 2002. Transposable elements and the evolution of genome size in eukaryotes. Genetica 115: 49-63. Kidwel l , M . G . and D . Lisch. 1997. Transposable elements as sources of variation in animals and plants. Proc Natl Acad Sci USA 94: 7704-7711. Kidwel l , M . G . and D.R . Lisch. 2001. Perspective: transposable elements, parasitic D N A , and genome evolution. Evolution IntJ Org Evolution 55: 1-24. Kiem, H.P. , S. Sellers, B . Thomasson, J . C Morris, J.F. Tisdale, P . A . Horn, P. Hematti, R. Adler, K . Kuramoto, B . Calmels et al. 2004. Long-term clinical and molecular follow-up of large animals receiving retrovirally transduced stem and progenitor cells: no progression to clonal hematopoiesis or leukemia. Mol Ther 9: 389-395. K i m , H.S. , O. Takenaka, and T.J. Crow. 1999. Cloning and nucleotide sequence of retroposons specific to hominoid primates derived from an endogenous retrovirus ( H E R V - K ) . AIDS Res Hum Retroviruses 15: 595-601. Kimberland, M . L . , V . Divoky, J. Prchal, U . Schwann, W . Berger, and H . H . Kazazian, Jr. 1999. Full-length human L I insertions retain the capacity for high frequency retrotransposition in cultured cells. Hum Mol Genet 8: 1557-1560. Kirkness, E.F. , V . Bafna, A . L . Halpern, S. Levy, K . Remington, D . B . Rusch, A . L . 132 Delcher, M . Pop, W. Wang, C M . Fraser et al. 2003. The dog genome: survey sequencing and comparative analysis. Science 301: 1898-1903. Kjellman, C , H.O. Sjogren, and B. Widegren. 1995. The Y chromosome: a graveyard for endogenous retroviruses. Gene 161: 163-170. Lahn, B.T., N . M . Pearson, and K. Jegalian. 2001. The human Y chromosome, in the light of evolution. Nat Rev Genet 2: 207-216. Landry, J.R., P. Medstrand, and D.L. Mager. 2001. Repetitive elements in the 5' untranslated region of a human zinc-finger gene modulate transcription and translation efficiency. Genomics 76: 110-116. Landry, J.R., A . Rouhi, P. Medstrand, and D.L. Mager. 2002. The Opitz syndrome gene M i d i is transcribed from a human endogenous retroviral promoter. Mol Biol Evol 19: 1934-1942. Langley, C.H., E. Montgomery, R. Hudson, N . Kaplan, and B. Charlesworth. 1988. On the role of unequal exchange in the containment of transposable element copy number. Genet Res 52: 223-235. Lavie, L. , M . Kitova, E. Maldener, E. Meese, and J. Mayer. 2005. CpG methylation directly regulates transcriptional activity of the human endogenous retrovirus family HERV-K(HML-2) . J Virol 79: 876-883. Leach, D.R. 1994. Long D N A palindromes, cruciform structures, genetic instability and secondary structure repair. Bioessays 16: 893-900. Leib-Mosch, C , W. Seifarth, and U . Schon. 2005. Influence of Human Endogenous Retroviruses on Cellular Gene Expression. In Retroviruses and Primate Genome Evolution (ed. E.D. Sverdlov), pp. 123-143. Landes Bioscience, Georgetown, Texas, USA. Lev-Maor, G., R. Sorek, N . Shomron, and G. Ast. 2003. The birth of an alternatively spliced exon: 3' splice-site selection in Alu exons. Science 300: 1288-1291. Lewinski, M . K . and F.D. Bushman. 2005. Retroviral D N A integration—mechanism and consequences. Adv Genet 55: 147-181. L i , W., P. Zhang, J.P. Fellers, B. Friebe, and B.S. Gi l l . 2004. Sequence composition, organization, and evolution of the core Triticeae genome. Plant J40: 500-511. L i , W.H. and D. Graur. 1991. Fundamentals of Molecular Evolution. Sinauer Associates, Sunderland, M A , USA. Liu, G., S. Zhao, J.A. Bailey, S .C Sahinalp, C. Alkan, E. Tuzun, E.D. Green, and E.E. Eichler. 2003. Analysis of primate genomic variation reveals a repeat-driven expansion of the human genome. Genome Res 13: 358-368. Liu, H. , H. Han, J. L i , and L. Wong. 2005. DNAFSMiner: a web-based software toolbox to recognize two types of functional sites in D N A sequences. Bioinformatics 21: 671-673. Lobachev, K.S., J.E. Stenger, O.G. Kozyreva, J. Jurka, D.A. Gordenin, and M . A . Resnick. 2000. Inverted Alu repeats unstable in yeast are excluded from the human genome. EmboJ 19: 3822-3830. Lorincz, M . C , D.R. Dickerson, M . Schmitt, and M . Groudine. 2004. Intragenic D N A methylation alters chromatin structure and elongation efficiency in mammalian cells. Nat Struct Mol Biol 11: 1068-1075. Ma, J. and J.L. Bennetzen. 2004. Rapid recent growth and divergence of rice nuclear genomes. Proc Natl Acad Sci USA 101: 12404-12410. Mager, D.L., D.G. Hunter, M . Schertzer, and J.D. Freeman. 1999. Endogenous retroviruses provide the primary polyadenylation signal for two new human genes 133 (HHLA2 and HHLA3). Genomics 59: 255-263. Mager, D.L. and P. Medstrand. 2003. Retroviral repeat sequences. In Nature Encyclopedia of the Human Genome, Volume 5, pp. 57-63. Macmillan Publishers Ltd., London, U . K . Majors, J. 1990. The structure and function of retroviral long terminal repeats. Curr Top Microbiol Immunol 157: 49-92. Makalowski, W. 2000. Genomic scrap yard: how genomes utilize all that junk. Gene 259: 61-67. Maksakova, I.A., M.T. Romanish, L. Gagnier, C A . Dunn, L . N . van de Lagemaat, and D.L. Mager. 2006. Retroviral elements and their hosts: insertional mutagenesis in the mouse germ line. PLoS Genetics 2: e2. Martin, A . M . , J.K. Kulski, C. Witt, P. Pontarotti, and F.T. Christiansen. 2002. Leukocyte Ig-like receptor complex (LRC) in mice and men. Trends Immunol 23: 81-88. McClintock, B. 1950. The origin and behavior of mutable loci in maize. Proc Natl Acad Sci USA 36: 344-355. McClintock, B. 1956. Controlling elements and the gene. Cold Spring Harb Symp Quant Biol 21: 197-216. McDonald, J.F. 1995. Transposable elements: possible catalysts of organismic evolution. Trends Ecol Evol 10: 123-126. McGinnis, S. and T.L. Madden. 2004. BLAST: at the core of a powerful and diverse set of sequence analysis tools. Nucleic Acids Res 32: W20-25. Medstrand, P., J.R. Landry, and D.L. Mager. 2001. Long terminal repeats are used as alternative promoters for the endothelin B receptor and apolipoprotein C-I genes in humans. J Biol Chem 276: 1896-1903. Medstrand, P. and D.L. Mager. 1998. Human-specific integrations of the H E R V - K endogenous retrovirus family. J Virol 72: 9782-9787. Medstrand, P., L . N . van de Lagemaat, C A . Dunn, J.R. Landry, D. Svenback, and D.L. Mager. 2005. Impact of transposable elements on the evolution of mammalian gene regulation. Cytogenet Genome Res 110: 342-352. Medstrand, P., L . N . van de Lagemaat, and D.L. Mager. 2002. Retroelement distributions in the human genome: variations associated with age and proximity to genes. Genome Res 12: 1483-1495. Meunier, J., A . Khelifi, V . Navratil, and L. Duret. 2005. Homology-dependent methylation in primate repetitive DNA. Proc Natl Acad Sci USA 102: 5471-5476. M i , S., X . Lee, X . L i , G . M . Veldman, H . Finnerty, L. Racie, E. LaVallie, X . Y . Tang, P. Edouard, S. Howes et al. 2000. Syncytin is a captive retroviral envelope protein involved in human placental morphogenesis. Nature 403: 785-789. Miskey, C , Z. Izsvak, K . Kawakami, and Z. Ivies. 2005. D N A transposons in vertebrate functional genomics. Cell Mol Life Sci 62: 629-641. Mitchell, R.S., B.F. Beitzel, A.R. Schroder, P. Shinn, H. Chen, C.C. Berry, J.R. Ecker, and F.D. Bushman. 2004. Retroviral D N A integration: A S L V , HIV, and M L V show distinct target site preferences. PLoS Biol 2: E234. Morgan, H.D., H.G. Sutherland, D.I. Martin, and E. Whitelaw. 1999. Epigenetic inheritance at the agouti locus in the mouse. Nat Genet 23: 314-318. Mouse Genome Sequencing Consortium. 2002. Initial sequencing and comparative analysis of the mouse genome. Nature 420: 520-562. Moynahan, M.E . and M . Jasin. 1997. Loss of heterozygosity induced by a chromosomal 134 double-strand break. Proc Natl Acad Sci USA9A: 8988-8993. Muratani, K. , T. Hada, Y . Yamamoto, T. Kaneko, Y . Shigeto, T. Ohue, J. Furuyama, and K. Higashino. 1991. Inactivation of the cholinesterase gene by Alu insertion: possible mechanism for human gene transposition. Proc Natl Acad Sci USA 88: 11315-11319. Murnane, J.P. and J.F. Morales. 1995. Use of a mammalian interspersed repetitive (MIR) element in the coding and processing sequences of mammalian genes. Nucleic Acids Res 23: 2837-2839. Nag, D.K., M . Fasullo, Z. Dong, and A. Tronnes. 2005. Inverted repeat-stimulated sister-chromatid exchange events are R A D 1-independent but reduced in a msh2 mutant. Nucleic Acids Res 33: 5243-5249. Nakaya, S.M., T.C. Hsu, S.J. Geraghty, M.J . Manco-Johnson, and A.R. Thompson. 2004. Severe hemophilia A due to a 1.3 kb factor VIII gene deletion including exon 24: homologous recombination between 41 bp within an A l u repeat sequence in introns 23 and 24. J Thromb Haemost 2: 1941-1945. Nekrutenko, A . and W.H. L i . 2001. Transposable elements are found in a large number of human protein-coding genes. Trends Genet 17: 619-621. Nigumann, P., K. Redik, K. Matlik, and M . Speek. 2002. Many human genes are transcribed from the antisense promoter of LI retrotransposon. Genomics 79: 628-634. Ono, M . , M . Kawakami, and T. Takezawa. 1987. A novel human nonviral retroposon derived from an endogenous retrovirus. Nucleic Acids Res 15: 8725-8737. Orgel, L.E. and F.H. Crick. 1980. Selfish DNA: the ultimate parasite. Nature 284: 604-607. Ostertag, E .M. , J.L. Goodier, Y . Zhang, and H.H. Kazazian, Jr. 2003. S V A elements are nonautonomous retrotransposons that cause disease in humans. Am J Hum Genet 73: 1444-1451. Ostertag, E . M . and H.H. Kazazian, Jr. 2001. Biology of mammalian L I retrotransposons. Annu Rev Genet 35: 501-538. Panet, A . and H . Cedar. 1977. Selective degradation of integrated murine leukemia proviral D N A by deoxyribonucleases. Cell 11: 933-940. Pavlicek, A. , K . Jabbari, J. Paces, V . Paces, J.V. Hejnar, and G. Bernardi. 2001. Similar integration but different stability of Alus and LINEs in the human genome. Gene 276: 39-45. Perepelitsa-Belancio, V . and P. Deininger. 2003. R N A truncation by premature polyadenylation attenuates human mobile element activity. Nat Genet 35: 363-366. Perna, N.T., M . A . Batzer, P.L. Deininger, and M . Stoneking. 1992. Alu insertion polymorphism: a new type of marker for human population studies. Hum Biol 64: 641-648. Pinsker, W., E. Haring, S. Hagemann, and W.J. Miller. 2001. The evolutionary life history of P transposons: from horizontal invaders to domesticated neogenes. Chromosoma 110: 148-158. Price, A . L . , N .C. Jones, and P.A. Pevzner. 2005. De novo identification of repeat families in large genomes. Bioinformatics 21 Suppl 1: i351-i358. Prudden, J., J.S. Evans, S.P. Hussey, B. Deans, P. O'Neill, J. Thacker, and T. Humphrey. 2003. Pathway utilization in response to a site-specific D N A double-strand break in fission yeast. EmboJll: 1419-1430. 135 Rabson, A . B . and B.J. Graves. 1997. Synthesis and Processing of Viral RNA. In Retroviruses (eds. J .M. Coffin S.H. Hughes, and H.E. Varmus), pp. 205-261. Cold Spring Harbor Laboratory Press, Plainview, New York, USA. Rat Genome Sequencing Project Consortium. 2004. Genome sequence of the Brown Norway rat yields insights into mammalian evolution. Nature 428: 493-521. Renard, M . , P.F. Varela, C. Letzelter, S. Duquerroy, F A . Rey, and T. Heidmann. 2005. Crystal structure of a pivotal domain of human syncytin-2, a 40 million years old endogenous retrovirus fusogenic envelope gene captured by primates. J Mol Biol 352: 1029-1034. Rosenberg, N . and P. Jolicoeur. 1997. Retroviral Pathogenesis. In Retroviruses (eds. J.M. Coffin S.H. Hughes, and H.E. Varmus), pp. 475-586. Cold Spring Harbor Laboratory Press, Plainview, New York, USA. Roy-Engel, A . M . , M . L . Carroll, E. Vogel, R.K. Garber, S.V. Nguyen, A . H . Salem, M A . Batzer, and P.L. Deininger. 2001. Alu insertion polymorphisms for the study of human genomic diversity. Genetics 159: 279-290. Salem, A . H . , G.E. Kilroy, W.S. Watkins, L.B. Jorde, and M A . Batzer. 2003a. Recently integrated Alu elements and human genomic diversity. Mol Biol Evol 20: 1349-1361. Salem, A . H . , D A . Ray, J. Xing, P A . Callinan, J.S. Myers, D.J. Hedges, R.K. Garber, D.J. Witherspoon, L .B . Jorde, and M A . Batzer. 2003b. Alu elements and hominid phylogenetics. Proc Natl Acad Sci USA 100: 12787-12791. Sankaranarayanan, K . and J.S. Wassom. 2005. Ionizing radiation and genetic risks XIV. Potential research directions in the post-genome era based on knowledge of repair of radiation-induced D N A double-strand breaks in mammalian somatic cells and the origin of deletions associated with human genomic disorders. Mutat Res 578: 333-370. SanMiguel, P., B.S. Gaut, A . Tikhonov, Y . Nakajima, and J.L. Bennetzen. 1998. The paleontology of intergene retrotransposons of maize. Nat Genet 20: 43-45. Schatz, D.G. 2004. Antigen receptor genes and the evolution of a recombinase. Semin Immunol 16: 245-256. Schmid, C W . 1998. Does SINE evolution preclude Alu function? Nucleic Acids Res 26: 4541-4550. Schroder, A.R., P. Shinn, H. Chen, C. Berry, J.R. Ecker, and F. Bushman. 2002. HIV-1 integration in the human genome favors active genes and local hotspots. Cell 110: 521-529. Sheen, F .M. , S.T. Sherry, G . M . Risch, M . Robichaux, I. Nasidze, M . Stoneking, M . A . Batzer, and G.D. Swergold. 2000. Reading between the LINEs: human genomic variation induced by LINE-1 retrotransposition. Genome Res 10: 1496-1508. Shen, L., L . C Wu, S. Sanlioglu, R. Chen, A.R. Mendoza, A.W. Dangel, M . C Carroll, W.B. Zipf, and C.Y. Yu. 1994. Structure and genetics of the partially duplicated gene RP located immediately upstream of the complement C4A and the C4B genes in the H L A class III region. Molecular cloning, exon-intron structure, composite retroposon, and breakpoint of gene duplication. J Biol Chem 269: 8466-8476. Shen, M.R., M . A . Batzer, and P.L. Deininger. 1991. Evolution of the master Alu gene(s). J Mol Evol 33: 311-320. Sironi, M . , G. Menozzi, G.P. Comi, N . Bresolin, R. Cagliani, and U . Pozzoli. 2005a. Fixation of conserved sequences shapes human intron size and influences 136 transposon-insertion dynamics. Trends Genet 21: 484-488. Sironi, M . , G. Menozzi, G.P. Comi, R. Cagliani, N . Bresolin, and U . Pozzoli. 2005b. Analysis of intronic conserved elements indicates that functional complexity might represent a major source of negative selection on non-coding sequences. Hum Mol Genet 14: 2533-2546. Smit, A.F. 1993. Identification of a new, abundant superfamily of mammalian LTR-transposons. Nucleic Acids Res 21: 1863-1872. Smit, A.F. 1999. Interspersed repeats and other mementos of transposable elements in mammalian genomes. Curr Opin Genet Dev 9: 657-663. Smit, A.F. and A .D . Riggs. 1995. MIRs are classic, tRNA-derived SINEs that amplified before the mammalian radiation. Nucleic Acids Res 23: 98-102. Smit, A.F. , G. Toth, A .D . Riggs, and J. Jurka. 1995. Ancestral, mammalian-wide subfamilies of LINE-1 repetitive sequences. J Mol Biol 246: 401-417. Sorek, R., G. Ast, and D. Graur. 2002. Alu-containing exons are alternatively spliced. Genome Res 12: 1060-1067. Sorek, R., G. Lev-Maor, M . Reznik, T. Dagan, F. Belinky, D. Graur, and G. Ast. 2004. Minimal conditions for exonization of intronic sequences: 5' splice site formation in alu exons. Mol Cell 14: 221-231. Stenger, J.E., K.S. Lobachev, D. Gordenin, T A . Darden, J. Jurka, and M . A . Resnick. 2001. Biased distribution of inverted and direct Alus in the human genome: implications for insertion, exclusion, and genome stability. Genome Res 11: 12-27. Sverdlov, E.D. 1998. Perpetually mobile footprints of ancient infections in human genome. FEBS Lett 428: 1-6. Sverdlov, E.D. 2000. Retroviruses and primate evolution. Bioessays 22: 161-171. Swergold, G.D. 1990. Identification, characterization, and cell specificity of a human LINE-1 promoter. Mol Cell Biol 10: 6718-6729. Symer, D.E., C. Connelly, S.T. Szak, E . M . Caputo, G.J. Cost, G. Parmigiani, and J.D. Boeke. 2002. Human 11 retrotransposition is associated with genetic instability in vivo. Cell 110: 327-338. Taruscio, D., G. Floridia, G.K. Zoraqi, A . Mantovani, and V . Falbo. 2002. Organization and integration sites in the human genome of endogenous retroviral sequences belonging to H E R V - E family. Mamm Genome 13: 216-222. Tchenio, T., J.F. Casella, and T. Heidmann. 2000. Members of the SRY family regulate the human LINE retrotransposons. Nucleic Acids Res 28: 411-415. Temin, H . M . 1982. Function of the retrovirus long terminal repeat. Cell 28: 3-5. Thompson, L . H . and D. Schild. 2002. Recombinational D N A repair and human disease. MutatRes 509: 49-78. Ting, C.N., M.P. Rosenberg, C M . Snow, L . C Samuelson, and M . H . Meisler. 1992. Endogenous retroviral sequences are required for tissue-specific expression of a human salivary amylase gene. Genes Dev 6: 1457-1465. Torti, C , L . M . Gomulski, D. Moralli, E. Raimondi, H . M . Robertson, P. Capy, G. Gasperi, and A.R. Malacrida. 2000. Evolution of different subfamilies of mariner elements within the medfly genome inferred from abundance and chromosomal distribution. Chromosoma 108: 523-532. Tournier, I., B.B. Paillerets, H. Sobol, D. Stoppa-Lyonnet, R. Lidereau, M . Barrois, S. Mazoyer, F. Coulet, A . Hardouin, A. Chompret et al. 2004. Significant contribution of germline BRCA2 rearrangements in male breast cancer families. 137 Cancer Res 64: 8143-8147. Tristem, M . 2000. Identification and characterization of novel human endogenous retrovirus families by phylogenetic screening of the human genome mapping project database. J Virol 74: 3715-3730. Turner, G., M . Barbulescu, M . Su, M.I. Jensen-Seaman, K . K . Kidd, and J. Lenz. 2001. Insertional polymorphisms of full-length endogenous retroviruses in humans. Curr Biol 11: 1531-1535. Ullu, E. and C. Tschudi. 1984. Alu sequences are processed 7SL R N A genes. Nature 312: 171-172. Urwin, D. and R.A. Lake. 2000. Structure of the Mesothelin/MPF gene and characterization of its promoter. Mol Cell Biol Res Commun 3: 26-32. van de Lagemaat, L .N . , J.R. Landry, D.L. Mager, and P. Medstrand. 2003. Transposable elements in mammals promote regulatory variation and diversification of genes with specialized functions. Trends Genet 19: 530-536. Venter, J.C., M.D. Adams, E.W. Myers, P.W. L i , R.J. Mural, G.G. Sutton, H.O. Smith, M . Yandell, C.A. Evans, R.A. Holt et al. 2001. The sequence of the human genome. Science 291: 1304-1351. von Melchner, H. , J.V. DeGregori, H. Rayburn, S. Reddy, C. Friedel, and H.E. Ruley. 1992. Selective disruption of genes expressed in totipotent embryonal stem cells. Genes Dev 6: 919-927. Walker, J.R., R.A. Corpina, and J. Goldberg. 2001. Structure of the K u heterodimer bound to D N A and its implications for double-strand break repair. Nature 412: 607-614. Wang, H. , J. Xing, D. Grover, D.J. Hedges, K. Han, J.A. Walker, and M . A . Batzer. 2005. S V A Elements: A Hominid-specific Retroposon Family. J Mol Biol 354: 994-1007. Ward, B.D., B.C. Hendrickson, T. Judkins, A . M . Deffenbaugh, B. Leclair, B.E. Ward, and T. Scholl. 2005. A multi-exonic BRCA1 deletion identified in multiple families through single nucleotide polymorphism haplotype pair analysis and gene amplification with widely dispersed primer sets. J Mol Diagn 7: 139-142. Watanabe, H. , A . Fujiyama, M . Hattori, T.D. Taylor, A . Toyoda, Y . Kuroki, H. Noguchi, A. BenKahla, H. Lehrach, R. Sudbrak et al. 2004. D N A sequence and comparative analysis of chimpanzee chromosome 22. Nature 429: 382-388. Wei, W., N . Gilbert, S.L. Ooi, J.F. Lawler, E . M . Ostertag, H.H. Kazazian, J.D. Boeke, and J.V. Moran. 2001. Human LI retrotransposition: cis preference versus trans complementation. Mol Cell Biol 21: 1429-1439. Whitelaw, E. and D.I. Martin. 2001. Retrotransposons as epigenetic mediators of phenotypic variation in mammals. Nat Genet 27: 361-365. Wilkinson, D.A., D.L. Mager, and J.C. Leong. 1994. Endogenous Human Retroviruses. In The Retroviridae (ed. J.A. Levy), pp. 465-535. Plenum Press, New York, N Y . Wu, X . , Y . L i , B. Crise, and S.M. Burgess. 2003. Transcription start regions in the human genome are favored targets for M L V integration. Science 300: 1749-1751. Yang, N . , L . Zhang, Y . Zhang, and H.H. Kazazian, Jr. 2003. A n important role for RUNX3 in human LI transcription and retrotransposition. Nucleic Acids Res 31: 4929-4940. Yoder, J.A., C P . Walsh, and T.H. Bestor. 1997. Cytosine methylation and the ecology of intragenomic parasites. Trends Genet 13: 335-340. Yohn, C.T., Z. Jiang, S.D. McGrath, K . E . Hayden, P. Khaitovich, M.E . Johnson, M . Y . 138 Eichler, J.D. McPherson, S. Zhao, S. Paabo et al. 2005. Lineage-specific expansions of retroviral insertions within the genomes of African great apes but not humans and orangutans. PLoS Biol 3: el 10. Yu, J., S. Hu, J. Wang, G.K. Wong, S. L i , B. Liu, Y. Deng, L. Dai, Y. Zhou, X. Zhang et al. 2002. A draft sequence of the rice genome (Oryza sativa L. ssp. indica). Science 296: 79-92. Yu, X., X. Zhu, W. Pi, J. Ling, L. Ko, Y. Takeda, and D. Tuan. 2005. The long terminal repeat (LTR) of ERV-9 human endogenous retrovirus binds to NF-Y in the assembly of an active LTR enhancer complex NF-Y/MZF1/GATA-2. J Biol Chem 280: 35184-35194. Zhang, Y., N . Zeleznik-Le, N . Emmanuel, N . Jayathilaka, J. Chen, P. Strissel, R. Strick, L. Li , M.B. Neilly, T. Taki et al. 2004. Characterization of genomic breakpoints in MLL and CBP in leukemia patients with t(l 1;16). Genes Chromosomes Cancer 41: 257-265. Zhu, Z.B., S.L. Hsieh, D.R. Bentley, R.D. Campbell, and J.E. Volanakis. 1992. A variable number of tandem repeats locus within the human complement C2 gene is associated with a retroposon derived from a human endogenous retrovirus. J Exp Med 175: 1783-1787. 139 Appendix A 140 Human-chimpanzee i n d e l l o c i assayed i n Rhesus monkey trace archive. Record s t r u c t u r e : 1: Header, showing human chromosome: chromosome s t a r t p o s i t i o n i n Ju l y 2003 0CSC genome browser: chromosome end p o s i t i o n ( i f necessary): chimpanzee s c a f f o l d name : s c a f f o l d s t a r t p o s i t i o n : s c a f f o l d end p o s i t i o n ( i f necessary): o r i e n t a t i o n of scaffold/chromosome alignment. 2: short d e s c r i p t i o n of case 3: M u l t i p l e sequence alignment of human, chimpanzee, and Rhesus sequences. Underlining h i g h l i g h t s i d e n t i c a l segments f l a n k i n g the in d e l s chrl:144298 621:14 4298777:scaffold_37562:1315854 : + ...imprecise d e l e t i o n of AluSx fragment i n chimpanzee CLUSTAL casein/1-256 GAAGAAATTTGGAAGAATTGCCACATGTGGAGCTATCTCTATATATAACATATACATATC g n l | t i I 518618788/314-567 GAAGAAATTTGGAAGAATTGCCATATATAGAGCTATCTCTGCATATAACATATACATATC caselc/1-101 GAAGAAATATGGAAGGATTGCCATATGTGGAGCCATCTCTACTTATAACAGA caselh/1-256 TACATATAACACCTGTAATCCCAGTACTTTGGGAGAATGAGGCAGGTGGATCACCTGAGG gnl|ti|518618788/314-567 TACATATAATGCCTGTAATCCCAACACTTTGGGAGGCTGAGGCAGGTGGATCACCTGAGG caselc/1-101 casein/1-256 TCAGGAGTTTGAGACCAGCCTGGCCAACATGGTGAAACCCCCGTCTCTACCAAAAATACA gnlIti|518618788/314-567 TCAGGAGTTTGAGACCGGCCTGGCCAAGATGGTGAAACCCCCTTCTGTACTAAAAATACA caselc/1-101 caselh/1-256 AAAATTAGCCGGGTGTGGTGGTACCAGCCCACTTCCCCCAGGCCCAATCCCAGAGATTGT g n l | t i I 518618788/314-567 AAAGTGAGCCAGGCATGGTGGCACCAGCCCACTTCCCCCAGGCCCAACCCCAGAGATTGT caselc/1-101 ACTGGCCCACCTCCCCCAGGCCCACCCCCAGATATTAT caselh/1-256 TAGATGTATCAGGAGC gnl|ti|518618788/314-567 TA—TCTATCAGGAGC caselc/1-101 CTATAAGGAGC chr2:50683419:50683739:scaffold_37688:19585334:-...AluY i n Rhesus, gene conversion to AluYa5 i n human, pr e c i s e d e l e t i o n i n chimpanzee CLUSTAL case2h/l-482 TGTAAGTTTCAGAATCATACTTTAAAAAA ATCTTTTTGGGGGCAGTTTTGTTTC g n l | t i I 508398655/154-589 TGTAAGCTGCAGAATCATACTTTAAAAAAAAAAAAAAATTTTGGGGGGCAGTTTTGTTTC case2c/l-163 TGTAAGTTTCAGAATCATACTTTTAAAAAA ATCTTTTTTGGGGCAGTTTTGTTTC case2h/l-482 AAAATTTAAATAAGAAACAAAAGTTCGGCCGGGCGCGGTGGCTCACGCCTGTAATCCCAG gnl | t i I 508398655/154-589 AAAATTTAAATAAGAAACAAAAGTTC ATCACGCCTGTAATCCCAG case2c/l-163 AAAATTTAAATAAGAAACAAAAGTTC case2h/l-4 82 CACTTTGGGAGGCCGAGGCGGGCGGATCACGAGGTCAGGAGATCGAGACCATCCCGGCTA gnl|ti|508398655/154-589 CACTTTGGGAGGCCGAGCCGGGCGGATCATGAGGTCAAGAAATCAAGACCATCCTGGCTA case2c/l-163 case2h/l-482 AAACGGTGAAA.CCCCGTCTCTACTAAAAATACAAAAAAAAATTAGCCGGGCGTAGTGGCG gnl|ti|508398655/154-589 ACATGGTGAAACCCTGTCTCTACTGAAAACACAAAAAA TTAGCTAGGCGTGGTGGCG case2c/l-163 case2h/l-482 GGCGCCTGTAGTCCCAGCTACTTGGGAGGCTGAGGCAGGAGAATAGCGTGAACCCGGGAG gnl | t i | 508398655/154-589 GGCGCCTGTA CTCGGGAGACTGAGGCAGGAGAATGGCGTGAACCCGAGAG case2c/l-163 case2h/l-482 GCGGAGCTTGCAGTGAGCCGAGATCCCGCCACTGCACTCCAGCCTGGGCGACAGAGCGAG g n l | t i I 508398655/154-589 GCGGAGCTTGCAGTGAGCAGTGATTGTGCCACTGCACTCCATCCTGGGTGACAGTGCAAG case2c/l-163 141 case2h/1-4 8 2 ACTCCGTCTCAAAAAAAAAAAAAAAAAAAAAAAGAAACAAAAGTTCAGAATATTGAAAGA gnl | t i | 508398655/154-589 ACTCTGTCTTAAAAAAAAAAAA TTCAAAATATCGAAAGA case2c/l-163 AGAATATTGAAAGA case2h/l-482 ATTATATGTTCTGTTGATATGGATAATAACAATATTAACTCCCCAAAACTCACTACAGGA gnl|ti|508398655/154-589 ATTATCTGTTCTGTTCATATGGATAA CAATATTAACTCCCCAACACTCACTACAGGA case2c/l-163 ATTATATGTTCTGTTGATATGGATAATAACAATATTAACTCCCCAAAACTCACTACAGGA case2h/l-482 AAACGTTA gnl|ti|508398655/154-589 AAACTTTA case2c/l-163 AAACGTTA chr2:69566745:scaffold_37 688:564230:564543:-. . .precise d e l e t i o n of AluY i n human CLUSTAL case3c/l-4 64 AAAAAAAAAAAAAAAAAGAAGTAGCTGATTCTTA TTTTTCATATAAGCTATCTTT g n l | t i I 507941191/90-555 AAAACAAACAAACAAAAAAAGTAACTGGTTCTTAATTTATTTTTCATATAAGCTATCTTT case3h/l-150 AAAAAAAAAAAAAAAAAGAAGTAGCTGATTCTTA- TTTTTCATATAAGCTATCTTT case3c/l-464 TCTTGGGGCTTCTTAAAAAAAATGGACAGCTCCAGGCCGGGCGCAGTGGCTCACGCCTGT gnl|ti|507941191/90-555 TCTTGTGGCTTCTTAAAAAAAAAAAAGAAC GGCCGGGCACGGTGGCTCAAGCCTGT case3h/l-150 TCTTGGGGTTTCTTAAAAAAA-TGGACAGCTCCA case3c/l-464 AATCCCAGCACTTTGGGAGGCCGAGGCGGGCGGATCACGAGGTCAGGAGATCGAGACCAT gnl | t i | 507941191/90-555 AATCCCAGCACTTTGGGAGGCCGAGACAGGCGGATCACGAGGTCAGGAGATCGAGACCAT case3h/l-150 case3c/l-464 CCTGGCTAACACGGTGAAACCCCGTCTCTACTAAAAA-TACAAAA-AATTAGCCGGGCGT g n l | t i I 507941191/90-555 CCTGGCTAACACGGTGAAACCCCGTTTTTATTAAAAAATACAAAACAACTAGCCGGGGGA case3h/l-150 case3c/l-464 GGTAGCGGGCGCCTGTAGTCCCAGCTACTCGGGAGGCTGAGGCAGGAGAATGGCGTGAAC gnl|ti|507941191/90-555 GGTGGGGGGTGCCTGTAGTCCCAGCTACTCGGGAGGGTGAGGCAGGAGAATGGGGTAAAC case3h/l-150 case3c/l-4 64 CCGGGAGGCGGAGCTTGCAGTGAGCCGAGATCGCGCCACTGCACTCCAGCCTGGGCGACA gnl|ti|507941191/90-555 CCGGGAGGGGGAGCTTGCAGTGAGCTGAGATCCGGCCACTGCACTCCAGCCTGGGCAACA case3h/l-150 case3c/l-4 64 GAGCGAGACTCCGTCTCAAAAAAAAAAAAAAAAAAAATGGACAGCTCCAGTTATTAACTA gnl | t i | 507941191/90-555 GAGCAAGACTCCGTTTCAAAAAAAAAAAAAAAAAAAA-GGACAGCTCCAGTTATTAACTA case3h/l-150 GTTATTAACTA case3c/l-464 GTAATGCTCTTAATTTCCTAAATATAAAATTAATTTGGCTAAGAACCCAGA gnl|ti|507941191/90-555 GTAATGCTCTTAATTTCCTAAATATAAAATTCATTTAGCTAAGAACCCAGA case3h/1-150 GTAATGCTCTTAATTTCCTAAATATAAAATTAATTTGGCTAAGAACCCAGA chr2:84195010:scaffold_36190:2002525:2002866:-... p r e c i s e d e l e t i o n of AluY i n human CLUSTAL case4c/l-491 GTGTACACATATGAATCTCAAAGCTGACATCTTTGTAACTAACATCTTAAAAAGCCTGAA gnl|ti|332419397/459-927 AGGTACACATATGAATCTCAAAGCTGACATCTTTGCAACTAAAATCTTAAAAAGCCTGAA case4h/l-150 GTGTACACATATGAATCTCAAAGCTGACATCTTTGTAACTAACATCTTAAAAAGCCTGAA case4c/l-4 91 ATCTTAAAAATCAACATCTTGGCCGGGCGCGGTGGCTCACGCCTGTAATCCCAGCACTTT gnl I t i I 332419397/459-927 ATCTTAACAATCAGCATGTT GGTGGCTCACGCCTGTAATCCTAGCACTTT case4h/l-150 ATCTTAAAAATCAACATCTT case4c/l-491 GGGAGGCCGAGGCGGGCGGATCACGAGGTCAGGAGATCGAGACCATCCTGGCTAACACGG gnl|ti|332419397/459-927 GGGAGGCCGGGACTGGTGGATCACGAGGTCAAGAGATGCAGACCATCGTGGCTAACATGG case4h/l-150 case4c/l-4 91 TGAAACCCCGTCTCTACT AAAAATACAAAAAATTAGCCGGGCGTGGTA 142 gnlIti|332419397/459-927 case4h/l-150 TGAAAACCCGTCTCTTCTTAAAAAAAAAAAAAAAAAAAAAAAAAATAGCCAGGGGAGGTG case4c/l-491 GCGGGCGCCTGTAGTCCCAGCTACTCGGGAGGCTGAGGCAGGAGAATGGCGTGAACCCGG gnl|ti|332419397/459-927 GTGGGCGCCTGTAGTCCCAGCTACTCGGGAGGCCGAGGCAGGAGAATGGTGTGAACCCGG case4h/l-150 case4c/l-491 GAGGCGGAGCTTGCAGTGAGCCGAGATCGCGCCACTGCACTCCAGCCTGGGCGACAGAGC gnlIti|332419397/459-927 GAGGCGGAGCTTGCAGTGAGCCGAGATCGCACCACTGCACTCCAGCCTGGGCGACAGAGC case4h/l-150 case4c/l-491 GAGACTCCGTCT C AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA gnl|ti|332419397/459-927 CAGACTCCATCTCAAACAAACAAACAAATGAACAAAAAA case4h/l-150 case4c/l-491 AATTCAACTTCTTAGT CAT TTAAAAAT CTGATATCTCACCTTCAT G AAAC AAAAAAGAGT gnl | t i | 332419397/459-927 TCAACATCTTAATCATTTAAAAATCTGATATCTCAGCTTCATGAAACAGAAAAGAGT case4h/1-150 AGTCATTTAAAAATCTAATATCTCAACTTCATGAAACAGAAAAGAGT case4c/l-491 AGGATCAGTGCAGTAAAAAGAAG g n l | t i I 332419397/459-927 AGGATCAGTGCAGTAGAAAGAAG case4h/l-150 AGGATCAGTGCAGTAGAAAGAAG chr2=157 669833:scaffold_37694:13104195=13104 426:-...rhesus sequence f i l l i n g t h i s i n d e l i s found mult i p l e times i n the human genome. Chimp sequence i s an L1PA2 without a discernable TSD. L i k e l y m u l t i p l e independent i n s e r t i o n s . CLUSTAL case5h/1-100 AGATTTAAAATCATTTTGATGATTTCTCTAAGATTATGTTGAGTTTCT gnl|ti|540008912/212-794 AGATTTTAAATCATTTTGATGATTTCTCTAAAATTATGTTGGGTTCCTTTTTTTTTTTTT case5c/1-331 AGATTTTAAATCATTTTGATGATTTCTCTAAGATTATGTTGAGTTTTT case5h/l-100 g n l I t i I 540008912/212-794 TTTTGAATAGCAAATAGTTTATTGGTAAGTACATGGTTTCAACAAGAGTAATAAATTCAC case5c/l-331 case5h/l-100 gnl | t i | 540008912/212-794 ATGAAAAGGAGACAATAATCAAGTCAAAAGAATAAATGCTTACTAATCATCAGAAAATCT case5c/l-331 case5h/l-100 gnl|ti|540008912/212-794 GTGGCCATTAGGGCTGGCACGTAAAAATCCAAAATCACTCAAAGGCCAAATCTTAAAGAA case5c/l-331 case5h/l-100 gnl|ti|540008912/212-794 GATTCGTCCTCTTATTAGTCCATATGGAATAGGTCCATAGTACACAGAATCTGTAGAATT case5c/l-331 AA case5h/l-100 gnl|ti|540008912/212-794 CTGTAGATTATCACCTTCTAACCAAACATGACCCATTGGCACCATAGGTCTGTTCTACAA case5c/l-331 AATTGAACAATGAGATCACATGGACACATGAAGGGGAATATCACACTCTGGGGACTGTGG case5h/l-100 gnl | t i | 540008912/212-794 TTCATTCAATTTTTACGGAAGTCACAGGCCTTCCAGAAAAAAAAAAAAATTAAAGCATGT case5c/l-331 TGGGGTGGGGGGAGGGGGGAGGGATAGCATTGGGAGATATACCTAAGGCTAGATGACGAG case5h/l-100 gnl|ti|540008912/212-794 TTCAAAGCATAGGTGGATGATCCATGATTTCAGGAATCCTCGGGCTCCAAAGAACCCTGA case5c/l-331 TTAGTGGGTGCAGCGCACCAGCATGGCACATGTATACATATGTAACTAACCTGCACAATG case5h/l-100 AAAACTTGG gnl|ti|540008912/212-794 AGACCCTCAACCAGGACACAGGTGGGCCTTTCTCACCTATGTTGGATTTTTAAAAGTTGG case5c/l-331 TGCACATGTACCCTAAAACTTAAAGTATAAAAACAAAAACAAAAAAA- - AAATAACTTGG case5h/1-100 TTTGTGTTAAATCTGTTCATTGATTTGGAGACTGACAGATATA gnl|ti|540008912/212-794 TTTGCATTAAATCTGTTCATTGATTTGGAGACTGACAGATATA case5c/1-331 TTTGTGTTAAATCTGTTCATTGATTTGGAGACTGACAGATATA 143 chr2:18382 9238:scaffold_37 634:13637014:13637174:+ ...non-transposable element sequence, l i k e l y p r e v i o u s l y i n s e r t e d with TSD, a l s o found on human chromosome 5, p r e c i s e d e l e t i o n i n human CLUSTAL case6c/l-260 GTCAGAGGGGTAAGAAAGCCAAGAGAGAGTAGTGATAAATGCT AAAAAAGAAAT AAGAAA gnl|ti|513283760/530-796 GTCAGAGGGGTAAGAAAGCCAAGAGAGAGTAGTGATAAATGCTAAAAAAGAAATAAGAAA case6h/l-100 GTCAGAGGGGTAAGAAAGCCAAGAGAGAGTAGTGATAAATGCTAAAAAAGA AAGAAA case 6c/1-2 60 GGAGTGGTCAGCCTCACACAGTCCTTCTGAGATTGTTAAGCAGATTACTTCCACCAGTAT g n l | t i I 513283760/530-796 GGAGTGGTCAGCCTCGCACAGTCCTTCTGAGATTGTTAAGCAGATTACTTCCATCAGTAT case6h/l-100 GGAGTGGTCAGC case6c/l-260 TGAGCCAGGAGTTGAGGTGGAAGTCACCATTGCAGATGCTTAAGTCAACTATTTTAATAA g n l | t i I 513283760/530-796 TGAGCCAGGAGTTGAGGTGGAAGTCACCATTGTAGATGCTTAAGTCAACTATTTTAATAA case6h/l-100 case 6c/1-2 60 ATTGATTACCAATTGTTTTAAAAAAAAAAAA AAGAAAGGAGTGGTCA gnl | t i | 513283760/530-796 ATTGATTACCAGTTGTTTTAAAAAAAAAAAAAAAAAAAAAAAAAA GAGTGGTCA case6h/l-100 case6c/l-260 GCAGTAAACATCAGTTGCGCAATAAGAAGACCA gnl|ti|513283760/530-796 GCAGTAAACATCAGTTGCCCAATAAGATCAAAA case6h/l-100 —AGTAAACATCAGTTGCGCAATAAGAAGACCA chr2:187720209:187720500:scaffold_37634=175 62752:+ ...AluY i n Rhesus, p a r t i a l d e l e t i o n and gene conversion to AluYb8 i n human, p r e c i s e d e l e t i o n i n chimpanzee CLUSTAL case7h/l-438 gnl I t i l 507795985/79-552 case7c/l-146 TGATATGTATGAGAAAGATACTGGTTTCTACATTTTGCTTTTAAATACTGTGAAGTAAAG TGATATGTATGAGAAAGATACTCGTTTCTACATTTTGCTTTTAAATACTATGAGGTAAAG TGATATGTATGAGAAAGATACTGGTTTCTACATTTTGCTTTTAAATACTGTGAAGTAAAG case7h/l-438 g n l | t i I 507795985/79-552 case7c/l-146 CACGAGACAACTTAAAAAAATATCTATAATG . GATGAGACAACTTAAAAAA-TATCTATAATGGGCCGGGCGCGGTGGCTCAAGCCTGTAAT CACGAGACAACTTAAAAAA-TATCTATAGTG case7h/l-438 g n l | t i l 507795985/7 9-552 case7c/l-146 AGCACTTTGGGAGGCCGAGGCGGGTGGATCATGAGGTCAGGAGATCGAGACCATCCT CCCAGCACTTTGGGAGGCCAAGACGGGCAGATCATGAGGTCAGGAGATCGAGACCATCAT case7h/l-438 gnl|ti|507795985/79-552 case7c/l-146 GGCTAACAAGGTGAAACCCCGTCTCTACTAAAA—ATACAAAAAATTAGCCGGGCGTGTT GGCTAACACGGTGAAACCCCGTCTATACTAAAAAAATACAAAAAACTAGCCAGGCGAGGT case7h/l-438 g n l | t i I 507795985/79-552 case7c/l-146 GGTGGGCGCCTGTAGTCCCAGCTACTCGGGAGGCTGAGGCAGGAGAATGGCGTGAACCCG GGTGGGCGCCTGTAGCCCCAGCT TGGGAGGCTGAGGCAGGAGAATGGCGTGAACCCG case7h/l-438 g n l | t i I 507795985/79-552 case7c/l-146 GGAAGCGGAGCTTGCAGTGAGCCGAGATTGCGCCACTGCAGTCTGCAGTCCGGCCTGGGC GGAGGCGGAGCTTGCAGTGAGCTGAGATCCGGCCACTGCACTC CAGCCTGGGT case7h/l-438 gnl|ti|507795985/7 9-552 case7c/l-146 GACAGAGCGAGACTCCGTCTCAAAAAAAAAAAAAAAAA- -AAAAAAAAT GACAGAGCGAGACTCCATCTCAAAAAAAAAAAAAAAAAAAATATATATATATATATATAT case7h/l-438 g n l | t i l 5077 95985/7 9-552 case7c/l-146 CTATAATGAAAATAGAGCAAAAATTACTGAAGTAGCATACAAATGACAAAGATGAGAGAA ATAAAATGAAAATAGAGCAAAAATTACTGAAGTACCATACAAATGACAAAGATGAGAGAA AAAATAGAGCAAAAATTACTGAAGTAGCATAAAA-TGACAAAGATGAGAGAA case7h/l-438 AGAAT 144 gnl I t i l 507795985/79-552 AGAAT case7c/l-146 AGAAT chr2:192411818:192412134:scaffold_37634:22298194:+ ...AluY i n Rhesus, gene conversion to AluYa5 i n human, pr e c i s e d e l e t i o n i n chimpanzee CLUSTAL case8h/l-476 AAAGAACTTTGCCTGTGTTGACTTTGTAAATGTTGTCTTAACCAAGCTTGGGCAACTATC gn l | t i I 498009529/103-591 AAAGAACTTTGCCTGTCTTGACTTTGTAAATGTTGTCTTAACCGAGCTTGAGCAACTATT case8c/l-160 AAAGAACTTTGCCTGTGTTGACTTTGTAAATGTTGTCTTAACCAAGCTTGAGCAACTATT case8h/l-47 6 TTTTTAAGAATCAAAAACACA—GCCGGGCGTGGTGGCTCACGCCTGTAATCCCAGCACT gnl Iti|498009529/103-591 TTTTTAAGAATCAAAAACACAAAGCCGGGCGCGGTGGCTCAAGCCTGTAATCCCAGCACT case8c/l-160 TTTTTAAGAATCAAAAACACAA case8h/l-47 6 TTGGGAGGCCGAGGGGGGTGGATCACGAGGTCAGGAGATCGAGACCATCCCGGCTAAAAC gnl | t i | 498009529/103-591 TTGGGAGGCCGAGGCGGGCGGATCACGAGGTCAGGAGATCGAGACCATCCTGGCTAACAT case8c/l-160 case8h/l-4 7 6 GGTGAAACCCCGTCTCTACTAAAAATACAAAAAA TTAGCCGGGCGTAGTGGCGGG gnl|ti|498009529/103-591 GGTGAAACCCCGTCTCTACTAAAAATACAAAAAAAAAAACTAGCCGGGCGTGGTGGCGGG case8c/l-160 case8h/l-476 CGCCTGTAGTCCCAGCTACTTGGGAGGCTGAGGCAGGAGAATGGCGTGAACCCGGGAGGC gnl |ti|498009529/103-591 CACCTGTAGTCCCAGCTACTCGG-AGACTGAGGCAGGAGAATGGCGTGAACCTGGGAGGC case8c/l-160 case8h/l-47 6 GGAGCTTGCAGTGAGCCGAGATCCCGCCGCTGCACTCCAGCCTGGGCGACAGAGCG—AG gnl|ti|498009529/103-591 GGAGCTTGCAGTGAGCCGAGATCGCACCACTGCACTCCAGCCTGGGTGACACAGCGCGAG case8c/l-160 case8h/l-47 6 ACTCCGTCTCAAAAAAAAAAAAAAAAAAAAAAGAATC AAAAACACGAAAAAGCCA gnl | t i | 498009529/103-591 ACTCCGTCTCAAAAAAAAAAAAACAAAAACAAAAACAAAACAAAAAACACAAAAAAGCCA case8c/l-160 AAAAGCCA case8h/l-476 CTCCACACAAAATATAATGCATCAAGTGTGGCTGCTGAATTACCGGAGTTAACATAGGTA gnl|ti|498009529/103-591 CCCCATATAAAATACAGTGCATCAGGTGTGGCTGCTAAATTACCAGAGTTAACATATGTA case8c/l-160 CTCCACACAAAATATAATGCATCAAGTGTGGCTGCTGAATTACTGGAGTTAACATAGGTA case8h/l-476 ' AGCACACACC gnl|ti|498009529/103-591 AACATACACC case8c/l-160 AGCACACACC chr2:210695342:210695583:scaffold_36996:2672593:+ ...precise d e l e t i o n of AluSg i n chimpanzee CLUSTAL case9h/1-363 TAACACATGTACTTCTAAATGTGTTTGAAGTTTGAGTCTTACTAACTTATGTAGAATTCA gnl|ti|562549776/185-546 TAATACATGCAGTTCTAAATGTGTTTGAAGTTTGAGTCTTACTGACTTATATAGAATTCA case9c/l-122 TAACACATGTACTTCTAAATGTGTTTGAAGTTTGAGTCTTACTAACTTATGTAGAATTCA case 9h/1-3 63 CATATTTTTCGGCCGGGCACGGTGACTCACGCC-TGTAATCCCAG—CACTTTGGGAGGC gnl|ti|562549776/185-546 CATATTTTTCGGCCAAACATGGTGAC—ACACC-TGTAATCACAG—AACTTTGGGAGGC case9c/l-122 CATATTTTTC case9h/l-3 63 CGAGGCAGACAGATCACAAGGTCAGGAGTTTGAGACCAGCCTGACCAACATGGTGAAACC gnl|ti|562549776/185-546 CGAGGCGGGCAGATCACAAGGTCAGGAGTTTGAGACCAGTCTGACCGACATGGTGAAACC case9c/l-122 case9h/l-363 CCCGTCTCTACTAAAAATA-AAAAATTAGCCGGGCATGGTGGCACGTGCCTGTAATCCCA gnl|ti|562549776/185-546 TCCATCTCTACTAAAAATACAAAAATTAGCCAGGCTTGGTGGCAGGCATCTGTAATCCCA case9c/l-122 case9h/l-3 63 GCTACTCAGGAGGCTGAAGAAGGAGAATCGCTTGAACCCGGGAGACGGAGGTTGCAGTGA 145 gnl|ti|562549776/185-546 GCTACTCAGGAGGCTGAGGCAGGAGAATCGCTGGAACCCAGGAGGCAGAGGTTGCAGTGA case9c/l-122 case9h/l-363 GCCGAGATATTTTTCACACAAAAACCTTAAATATTACAGTGCAGTGGTTAGCAACTCTGA gnl|ti|562549776/185-546 GCCAAGATATTTTTCACACGAAAACCTTAAATATTACAGTGCAGTGGTTAGCAACTCTGA case9c/l-122 ACACAAAAACCTTAAATATTACAGTGCAGTGATTAGCAACTCTGA case9h/l-363 AAGTTTG g n l | t i I 562549776/185-546 AAGTTTG case9c/l-122 AAGTTTG chr2:231119183=231119489:scaffold_34265=2315868:+ ...AluY i n Rhesus, gene conversion to AluYg6 i n human, p r e c i s e d e l e t i o n i n chimpanzee CLUSTAL caselOh/1-461 TCAGTGCA-TTTATTTTATATATTATTTCTATAATGTGCATATTTAATAACAAATAACAT gnl|ti|540018070/562-1046 TCAATGCA-TTTATTTTATATATTATTTCTATAATGTGCATATTTAATAACAAATAACAT caselOc/1-156 TCAGTGTAGTTTATTTTATATATTATTTCTATAATGTGCATATTTAATAACAAATAACAT caselOh/1-461 TTATATAAAGTATGTTTA GGCCGGGCGCGGTGGCTCACGCCTGTAA gnl|ti|540018070/562-104 6 TTATATAAAGTATGTTTAATATATTAAGTCTAGGCCGGGCGCGGTGGCTCACGCCTGTAA casel0c/l-156 TTATATAAAGTATGTTTAATATATTAAGTCTA caselOh/1-461 TCCCAGCACTTTGGGAGGCCGAGACGGGCGGATCACGAGGTCAGGAGATCGAGACCATCC g n l | t i I 540018070/562-104 6 TCCCAGCACTTTGGAAGGCCGAGACAGGCAGATCATGAGGTCAGGAGATCGAGATCATCC casel0c/l-156 case10h/1-461 TGGCTAACACGGTGAAACCCCGTCTCTACTAAAAATACAAAAA TTAGCCAGGCA g n l | t i I 540018070/562-104 6 TGGCTAACACGGTGAAACCCCCTCTCTACTAAAAATACAAAAAAAAAAATTAGCCGGGCG casel0c/l-156 caselOh/1-461 TGGTGGCGTGCGCCTGTAGTCCCAGCTACACGGGAGGCTGAGGCAGGAGAATGGCGCGAA gnl|ti|540018070/562-104 6 TGGTGGTGGGCGCCTGTAGTCCCAGCTACACGGGAGGCTGAGGCAGGAGAATGGCATAAA casel0c/l-156 case 10h/1-4 61 CCCGGGAGGCGGAGCTTGCAGTGAGTCGAGATCGCGCCACTGCACTCCAGCCTGGGCAAC g n l | t i I 540018070/562-1046 CCCGGGGAGCGGAGCTTGCAGTGAGCTGAGATCGCGCCACTGCACTCCAGCCTGGGCAAC casel0c/l-156 caselOh/1-461 AGAGCTAAACTCCGTCTCAAAAAAAAAAAAAA AAAGTATGTTTAATATATTAAGTC gnl | t i I 540018070/562-1046 AGAGCGAGACTCCGTTTCAAAAAAAAAAAAAAAAATATATATATATATATATATAAAGTC casel0c/l-156 caselOh/1-461 TATTCTAAGGAGTTAATTTACTGAATTATTTCCTGTAATGCAACAGAGTTAATTAAATTA gnl|ti|540018070/562-1046 TATTCTAAGAAGTTGCTTTACTGAATTATTTCCTGTAATGCAGCAGAGTTAATTATATTA caselOc/1-156 —TTCTAAGGAGTTAATTTACTGAATTATTTCCTGTAATGCAACAGAGTTAATTAAATTA caselOh/1-461 ATAAGT gnl|ti|540018070/562-1046 ATAAGT caselOc/1-156 ATAAAT Chr2=234434078=234434368:scaffold_37338:1917127:-...AluY i n Rhesus, gene conversion to AluYb8 i n human, pr e c i s e d e l e t i o n i n chimpanzee CLUSTAL casellh/1-437 GAAACTAGTTATTGTCAGAAGAGACCATTGGGATGAAAAGTGTGTATCTTCGAAACCACT gnl|ti|538232282/352-812 GAAACTAGTTATTGTCAGAAGAGACCATTGGGATGAAAAGTGTGTATCTTCAAAACCACT casellc/1-147 GAAACTAGTTATTGTCAGAAGAGACCATTGGGATGAAAAGTGTGTATCTTCAAAACCACT casellh/1-437 AAAGAAAAACTC ACACTTTGGGAGGCC gnl|ti|538232282/352-812 AAAGAAAAACTCGGCCGGGCACGGTGGCTCAAGCCTGTAATCCCAGCACTTTGGGAGGCC casellc/1-147 AAAGAAAAACTC casellh/1-437 GAGGCGGGTGGATCATGAGGTCAGGAGATCAAGACCATCCTGGCTAACAAGGTGAAACCC 146 gnl|ti|538232282/352-812 casellc/1-147 GAGATGGGTGGATCACGAAGTCAGGAGATCGAGACCATCCTGGCTAACAGGGTGAAACCC casellh/1-437 TGTCTCTACTAAAAA-TACAAA AAATTAGCCGGGCGCGGTGGCGGGCGCCTGTAGT gnl | t i | 538232282/352-812 CGTCTCTACTAAAAAATACAAAAAAAAAATTAGCCGGGCGTGGTGGCGGGTGCCTGTAGT casellc/1-147 casellh/1-437 CCCAGCTACTCGGGAGGCTGAGGCAGGAGAATGGCGTGAACCCGGGAAGCGAAGCTTGCA gnl|ti|538232282/352-812 CCCAGCTACTCGGGAGGCTGAGGCAGGAGAATGGCCTGAACCCGGGAGGCAGAGCTTGCA casellc/1-147 casellh/1-4 37 GTGAGCCGAGATTGCACCACTGCAGTCCGCAGTCCGGCCTGGGCGACAGAGCGAGACTCC gnl | t i I 538232282/352-812 GTGACCTGAGATCCGGCCACTGCACTCCA GCCTGGGTGACAGAGCAAGACTCC casellc/1-147 casellh/1-437 GTCTCAAAAAAAAAAAAAAGAAAAAAAGAAAGAAAAACTCAGTCTGTACCTTCTATAATA gnl | t i I 538232282/352-812 GTCTCAAAAAAAAAAAAAAAAAAA GAAAAACTCAGTCTGTACCTTCTATAATA casellc/1-147 AGTCTGTACCTTCTATAATA casellh/1-437 ATAATTAGTAATGCCAGTAACAGCAGGTAACATTTATTGAATGTATACAGTGTGT gnl|ti|538232282/352-812 ATAATTAGTAATGCCAGTAACAGAAAGTAATATTTATTGAATGTGTACAATGTGT casellc/1-147 ATAATTAGTAATGCCAGTAACAGCAGGTAACATTTATTGAATGTATACAGTGTGT chr3=3802176:scaffold_32934:3840390:3840497:+ ...imprecise d e l e t i o n of L2 fragment i n human, no s i m i l a r i t y at breakpoint CLUSTAL casel2c/l-207 TAATTCCTCATGTCCCCACCTTAGCCCCCATATGATCCTCTCAGGCCTTGCTAAAGCTCA gnl|ti|583293545/557-763 TCATCCCTCATGTCCCCACCTCTGCCCCCACATGATCCTCTCAGGCCTTGCTAAAGCTGA casel2h/l-101 TAATTCCTCATGTCCCCACCTTAGCCCCCATATGATCCTCTCAGGCCTTGTT casel2c/l-207 GAGCCAAAAAACAGTTCTTAGAACACAGTAGAAACTCAACAAATATTTGCTGAATTAGTA gnl|ti|583293545/557-763 GAGCCAAAAAACAGTTCTTAGAACACAGTAGAAACTCAACAAATATTTGCTGAATTAGTG casel2h/l-101 case12c/1-207 TCCATGTTCGTCTAGTCTCCCAGTTCATAGGCCATCATGTTTTACATGTAGCTGATGTTT gn l | t i I 583293545/557-763 TCCATGTTTGTCTAGTCTCCCAGTTCATAGGCCATCATGTTTTACAAGTAGCTGATGTTT casel2h/l-101 GTTTTACATGTAGCTGATGTTT casel2c/l-207 GTCGATGTCTACTGAGTCAAATATAGA gnl|ti|583293545/557-763 GTCGATGTCTACTGAGTCAAATATAGA casel2h/l-101 GTCGATGTCTACTGAGTCAAATATAGA chr3=34069680:scaffold_37683=15182979=15183196:-...independent i n s e r t i o n s of an AluY i n Rhesus and L1PA2 i n chimpanzee i n the same s i t e CLUSTAL casel3c/285-601 AAGCAGATGGGGGTCAGGAAGCAAGAAGAGGTAGGTTAGAAAGCCTTTACGGAAGGGGAA gnl|ti|583406125/478-897 AAG-GGATGGGGGTCAGGAAGCAAGAAGAGGTAGATTAGAAAGGCTTTACCAGCCGGGCG casel3h/l-99 AAG-AGATGGGGGTCAGGAAGCAAGAAGAGGTAGATTAGAAAGGCTTTAC casel3c/285-601 TA CCATACTCTGGGGACTGTGGTGGG--GAGGGGGGAGG gnl Iti I 583406125/478-897 CGGTGGCTCACGCCTGTAATCCCAGAACTTTGGCAGGCCGAGGCGGGCGGATCACGAGGT casel3h/l-99 casel3c/285-601 — GGGGAGGGATAGCAT- -TGGGAGATATACCTAA TGCTAGA gnl|ti|583406125/478-897 CAGGAGATCGAGACCATCCTGGCTAACACAGTGAAACCCCGTCTCTACTAAAAATACAAA casel3h/l-99 easel 3c/2 85-601 TGACGAGT—TAGTGGGTGCAGCGCACCAGCATGGC gnl|ti|583406125/478-897 AAGAAAAAAATTAGCCGGGCATGGTGGCGAGCGCCTGTAGTCGCAGC-TACTCGGGAGGC casel3h/l-99 casel3c/285-601 ACATGTATACATATGTAACTAACCTG CACAATGTGCACA gnl|ti|583406125/478-897 TGAGGCAGGAGAATGGCGTGAACCTGGGAGGCGGAGCTTGCAGTGAGCTGGATCGCGCCA 147 casel3h/l-99 casel3c/285-601 -TGTACCCTAA AACTTAAAGTATAATAATA AAAAAAAAAAAAAAAAAAGAA gnl|ti|583406125/478-897 CTGCACTCCAGCCTGGGTGAAAGAGCGAGACTCCTTCTCAAAAGAAAGAAAAAAAAAGAA casel3h/l-99 casel3c/285-601 AGCCTTTACCAAAAAAAA CATGGTGTTTGAACTGATACTTAAACTGGTTCTTAAGCT gnl|ti|583406125/478-897 AGGCTTTACCAAAAAAAAAACCACAGTGTTTGAACTGATACTTAAGCTGGTTCTTAAGCT easel 3h/l-99 CAAAAAAAA CATGGTGTTTGAACTGATACTTAAACTGGTTCTTAAGCT casel3c/285-601 GG gnl|ti|583406125/478-897 GG casel3h/l-99 GG chr3:127318836=127319143:scaffold_36943=880680:-...precise d e l e t i o n of AluSg i n chimpanzee CLUSTAL casel4h/l-4 62 CGGTGAGTATTCACTTAGCACCCAGGATCTT TAAACCAACCAGTGCAT g n l | t i I 501884074/122-632 CGGTGAGTATTCACTTAGCATCCGGGATCTTCACACTCTGCCCTAAACCAACCAGTGCAT casel4c/l-155 CGGTGAGTATTCACTTAGCACCTAGGATCTT TAAACCAACCAGTGCAT casel4h/l-4 62 TCCCTTCTGAAGAGCCTTCAACTTCACTTTAAAAAATCCTGTGATGGGGCGGGCGTGGTG gnl|ti|501884074/122-632 TCACTTCTGAGGATCCTTCAACTTCACTTAAAAAAATCCTGTGACGGGGCGGGCATGGTG case 14c/1-155 TCCCTTCTGAAGAGCCTTCAACTTCACTTTAAAAAATCCTGTGATGG case14h/1-462 GCTCATGCCTGCAATCCCAGCACTTTGGGAGGTCAAGGTGGGCAGATCACGAGGTCAGGA gnl|ti|501884074/122-632 GCTCACGCCTGTAATCCCAGCACTTTGGGAGGCCAAGGCGGGCGGATCACCAGGTCAGGA casel4c/l-155 casel4h/l-462 GTTCGACACCAGCCTTACCAACATGGTGAAACCCTGTCTCTACTAAAAATACAAAAATTA gnl | t i | 501884074/122-632 GCTCAACACCAGCCTTACCAACATGGTGAAACCCTGTCTTTACTAAAAATACAAAAATTA casel4c/l-155 case14h/1-462 GCCGGGTGTGGTGACACGCGCCTGTAATCCCAGCTACTCAGGAGGCTGAGGCAGGAGAAT gnl|ti|501884074/122-632 GCCAGGTGTGGTGGAGTGCGCCTGTAATCCCAGCTACTCAGGAGGCTGAGGCAGGAGAAT casel4c/l-155 case14h/1-462 CACTTGAATCCGGGAGGTGGAGGTTGCAGTGAGCCGAAATCATGCCACTGCACTCCAGCC gnl|ti|501884074/122-632 CACTTCAACCCGGGAGGTGGAGGTTGCAGTGAGCCGCGATCATGCCACTGCACTCCAGCC casel4c/l-155 casel4h/l-462 TGGGCAACAGAACGAGACTTTGTCTAAAAAAAAAAAAA gnl | t i | 501884074/122-632 TGGGCGACAGAGTGAGATTCTGTCAAAAAAAAAAAAAAAAAAAAAAAAACACACACACAC casel4c/l-155 casel4h/l-462 AAAAATCCTGTGATGGCAAAGACGTTCT-CAGGCTAAATTCAACTC gnl|ti|501884074/122-632 ACAACAAAACAAAATAAAATGCTGTGATGGCAAAGACGTTTTTCAGGCTAAATTCAACTC easel 4c/1-155 CAAAGACGTTCT-CAGGCTAAATTCAACTC casel4h/l-462 ATGTATTTTTTACATACATAATATTTGAAGG gnl|ti|501884074/122-632 ATGTATTTTTTACATAGATAATATTTGAAGG casel4c/l-155 ATGTATTTTTTACATACATAATATTTGAAGG Chr4=62743877.-62744205:scaffold_37623=10184651:+ ...AluY i n Rhesus, p a r t i a l TSD d e l e t i o n and gene conversion to AluYb8 i n human, pr e c i s e d e l e t i o n i n chimpanzee CLUSTAL casel5h/l-494 AGTGACAAAGTGCAGGTCTACAGAACAAAGGGCACAAATAAAACTAGGCAATTTTGTGTG gnl|ti|523759330/256-733 ACTGACAAAGTGCAGGTCTACAGAAAAAAAGGCACAAATAAAACTAGGCAATTTTGTGTG case15c/l-166 AGTGACAAAGTGCAGGTCTACAGAACAAAGGGCACAAATAAAACTAGGCAATTTTGTGTG casel5h/l-494 TTGACTATAAAAGAGCATTTTG GGCCGGGCGCGGTG gnl|ti|523759330/256-733 TTGACTATAAAAGAGCATTTTGATGTTGTTGAAAATATTTTACACAGGCCGGGCGCGGTG 148 casel5c/l-166 TTGACTATAAAATAGCATTTTGATGTCATTGAAAATATTTTACACA-case15h/1-494 GCTCACGCCTGTAATCCCAGCACTTTGGGAGGCCGAGGCGGGTGGATCATGAGGTCAGGA g n l | t i I 523759330/256-733 GCTCAAGCCTGTAATCCCAGCACTTTGGGAGGCCAAGACGGGCGGATCACGAGGTCAGGA casel5c/l-166 case 15h/1-4 94 GATCGAGACCATCCTGACTAACAAGGTGAAACCCCGTCTCTACTAAAAA—TACAAAAAA gnl | t i I 523759330/256-733 GATCGAGACCATCCTGGCTAACACAGTGAAACCCCGTCTCTACTAAAAAAATACAAAAAA casel5c/l-166 casel5h/l-494 TTAGCCGGGCGCGGTGGTGGGCGCCTGTAGTCCCAGCTACTCGGGAGGCTGAGGCAGGAG g n l | t i I 523759330/256-733 CTAGCCGGGCGAGGTGGCGGGCGCCTGTAGTCCCAGCTACTCAGGAGGCTGAGGCAAGAG casel5c/l-166 casel5h/l-494 AATGGCGTGAACCCGGGAAGCGGAGCTTGCAGTGAGCCGAGATTGCGCCACTGCAGTCCG gnl|ti|523759330/256-733 AATGGCGTAAATCCGGGAGGCGGAGCTTGCAGTGAGCCGACATCCGGCCACTGCACTCCA casel5c/l-166 easel 5h/l-4 94 CAGTCCGGCCTGGGCGACAGAGCGAGACTCCGTCTCAAAAAAAAAAAAAAAAAAAAAAAA gnl | t i | 523759330/256-733 GCCTGGGCAACAGAGCGAGACTCCGCCTCAAAAAAAAAAAAA casel5c/l-166 casel5h/l-494 AAAAAAGAGCATTTTGATGTCGTTGAAAATATTTTACACAAATGAAAAAGTGGTGATGGT gnl | t i I 523759330/256-733 GAAAATATTTTACACAAATGAAAAAGTGGTGATGGT casel5c/l-166 AATGAAAAAGTGGTGATGGT casel5h/l-494 TATCACGTGAGGGGGTTCTGTGGTCTCCCCTTCTCTTAGT gnl|ti|523759330/256-733 TATCATGTGAAGGGGTTCTGTGGTCTCCCTTTCTCTTAGT easel5c/1-166 TATCACATGAGGGGGTTCTGTGGTCTCCCCTTCTCTTAGT chr4:110847016:110847328:scaffold_37491:1921071:+ . . .precise d e l e t i o n of AluY i n chimpanzee CLUSTAL easel6h/1-4 7 0 TCATTTGCTTTATTTTAGAAAAGCCTATTAGTACATTATAATTCAGTACTAGAACTTCAA gnl|ti|540783035/118-571 TCATTTGCTTTATTTTAGAAAAGCCTATTAGTACATTATAATTCAGTACTAGAACTTCAA casel6c/l-158 TCATTTGCTTTATTTTAGAAAAGCTTATTAGTACATTATAATTCAGTACTAGAACTTCAA easel 6h/l-470 TTATTTTATTAAAAAGTCCACTCCAG-CCGGGCGCGGTGGCTCACGCCTGTAATCCCAGC gnl|ti|540783035/118-571 TTATTTTATTAAAAAGTCCACTCCGGGCTGGGCATGGTGGCTCACGCCTGTAATCCCAGC casel6c/l-158 TTATTTTATTAAAAAGTCCACTCCA case16h/1-470 ACTTTGGGAGGCCGAGGCGGGCGGATCACGAGGTCAGGAGATCGAGACCATCCTGGCTAA gnl|ti|540783035/118-571 ACTTTGGGAGGCTAAGGCAGGCAGATCATGAGGTCAGGAGATCGAGACCATCCTGGCAAA casel6c/l-158 easel6h/1-4 7 0 CACGGTGAAACCCCGTCTCTACTAAAAATACAAAAAATTAGCCGGGCGTGGTAGCGGGCG gnl|ti|540783035/118-571 CACGGTGAAACCCCGTCTCTACTAAATATACAAAAAATTAGCTGGGCAAGGTGGCGGGCG casel6c/l-158 casel6h/l-470 CCTGTAGTCCCAGCTACTCGGGAGGCTGAGGCAGGAGAATGGCGTGAACCCGGGAGGCGG g n l | t i I 540783035/118-571 CCTGTAGTCCCAGCTTCTCGGGAGGCTGAGGCAGGAGAATGGCGTGAACCCGGGAGGCGG casel6c/l-158 casel6h/l-470 AGCTTGCAGTGAGCCGAGATCGCGCCACTGCACTCCAGCCTGGGCGACAGAGCGAGACTC gnl | t i | 540783035/118-571 AGCTTGCAGTGAGCCGAGATCGCGCCACTGCACTCCAGCCTGGGGGACAGAGCGAGACTC casel6c/l-158 easel 6h/l-470 CGTCTCAAAAAAAAAAAAAAAAAAAAAAGTCCGCTCCAAGTATGTATGTTTTGAGTGTTA gnl | t i | 540783035/118-571 CGTCTCAAAAA GCCCACTCCAAGTATGTATGTTTTGAGTGTTG casel6c/l-158 AGTATGTATGTTTTGAGTGTTA easel6h/l-470 CATTAGTTGTTAAAGTTGGTTGCACTTTTGGCTAGTGTTTAAAAGGTGTCA gnl|ti|540783035/118-571 CATTAGTTGTTAACTTAGGTTGCACTTCTGGCTAGTGTTTAAAAGGTGTCA casel6c/l-158 CATTAGTTGTTAAAGTTGGTTGCACTTTTGGCTAGTGTTTAAAAGGTATCA 149 chr4:113908780:113908932:scaffold_37491:5060691: + ....AluY i n Rhesus, p a r t i a l deletion/gene conversion to AluYb9 i n human, p r e c i s e d e l e t i o n i n chimpanzee CLUSTAL casel7h/l-252 TATGAAATTTGTGTTGTGTCTTCAGGTGATTTAAAAAAATATATGACAT casel7c/l-100 TATGAAATTTGTGTTGTGTCTTC AGGTGATTTAAAAAAATATATGACAT gnl | t i | 541340560/355-730 TATGAAATTTGTGTTGTGTCTTCAGG GGCGCGGTGGC casel7h/l-252 casel7c/l-100 gnl | t i I 541340560/355-730 TCAAGCCTGTAATCCCAGCACTTTGGGAGGCCGAGGCGGGCGGATCACAAGGTCAGGAGA casel7h/l-252 casel7c/l-100 gnl|ti|541340560/355-730 TCGAGACCACAGTGAAACCCCGTCTCTACTAAAAATACAAAAAATTAGCCGGGCGCGGTG casel7h/l-252 CGG casel7c/l-100 g n l I t i I 541340560/355-730 ACGGGCGCCTGTAGTCCCAGCGACTCAGGAGGCTGAGGCAGGAGAATGGCGGGAACCCGG casel7h/l-252 GAAGCGGAGCTTGCAGTGAGCCGAGATTGCGCCACTGCAGTCCGCAGTCCAGCCTGGGCG casel7c/l-100 '• gnl|ti|541340560/355-730 GAGGCGGAGCTTGCAGTGAGCCGAGATCGCGCCACTGCACTCC AGCCTGTGCA casel7h/l-252 ACAGAGCGAGACTCCGTCTCAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAATATAT casel7c/l-100 gnl|ti|541340560/355-730 ACAGCGTGAGACTCCGTCTCACACGNCCNNNNNNNACATNAAAAAAA casel7h/l-252 ATATATATATATATATATATATATGACATCTATCCTGTCAAGTTGATGTTAATTTGG-AT casel7c/l-100 CTATCCTGTCAAGTTGATGTTAATTTGG-AT gnl | t i | 541340560/355-730 TGACATCTATCCCGTTAAGTTGATGTTGATTTTGCAT casel7h/l-252 AGAATTGGC-TTTATAGTTGTA casel7c/l-100 AGAATTGGC-TTTATAGTTGTA gnl|ti|541340560/355-730 GGAATTGCCCTTTCCATTTGTA chr4:127295460:127295786:scaffold_34705:5896785:-... independent i n s e r t i o n s of L1PA2 i n human, and AluY i n Rhesus. Imprecise l o c a l i z a t i o n due to m i c r o d e l e t i o n here? CLUSTAL casel8h/209-634 gnl|ti|558352008/2 93-7 68 casel8c/l-114 ATAGTAATCTAAATTGCTCCAGACAAATATTTTCTGTTTTAAAAATAGTA ATAGTCGTCTAAACTGATCTCGACAAAGATTTTCTGTTTTAAAAATAGTATTAACTACGT ATAGTAATCTAAATTGATCCAGACAAATATTTTCTGTTTTAAAAATAGTATTAACTACAT casel8h/209-634 gnl|ti|558352008/293-7 68 casel8c/l-114 AGGACATGGATGAAATTGGAA TATAAGAAAATTTAGCAGGGTGCAGTCGTTCGTGCCTGTAATCCCGCACTTTGGGAGGGC TATTAGAAAATTT casel8h/209-634 gnl|ti|558352008/2 93-7 68 casel8c/l-114 ATCATCATTCTCAGTAAACTATCGCAAGAACAAAAAACCAAACACCGCATATTCTCACTC GAGGCGGGTGGATCACGAAGTCAGGAGATCAAGACCACCCTGGCTAACACAGTGAAACCC casel8h/209-634 ATAGGTGGGAATTGAACAATGAGATCACATGGACACAGGAAGGGGAATATCACACTCTGG gnl|ti|558352008/293-768 CATCTTTCCTAAAAATACAAAAAAATTAACCAGGCATTGTGGCGGGCGCCTGTAGTTCCA casel8c/l-114 casel8h/209-634 gnl|ti|558352008/293-7 68 casel8c/l-114 GGACTGTGGTGGGGTGGGGGGAGGGGGGAGGGATAGCATTGGGAGATATACCTAATGCTA GCTACTCGGGAGGCTGAGGCAGGAGAATGGCGTGAACCTGGGAGGCAGAGCTTGCGGTGA casel8h/209-634 gnl|ti|558352008/293-7 68 casel8c/l-114 GATGACGAGTTAGTGGGTGCAGCGCA-CCAGCATGGCACATGTATACATATGTAACTAAC GCCAAGATCACACCACTGCACTCCAGCCTGGGAGGGAAAGGTGTTTTTGGGAGACAGAGC casel8h/209-634 CTGCACAATGTGCACATGTACCCTAAAACTTAAAGTATAATAAAAAAATAAATAAATAAA 150 gnl | t i | 558352008/293-768 AAAACTCCGTATCAAAAAAAAAAAAAAAAAAAACCACACAAAAAACTCCGTCTCAAAAAA casel8c/l-114 casel8h/209-634 TAAAAAAGAAAATTTAAATAGGTACAATGACCATTTATAGAAACATAATTCACTAG gnl|ti|558352008/293-768 AAAAAAAAAAAAATTACATAGGTATAATGACCATTTATAGAAAAATAATTCACTGG casel8c/l-114 AAATAGGTACAATGACCATTTATAGAAACATAATTCACTAG Chr4:180115809:scaffold_31924:122 67927:12268281:+ ...imprecise d e l e t i o n of AluY i n human, but i n v o l v i n g TSD and f o r t u i t o u s upstream match CLUSTAL casel9c/l-504 TGATCCTGGGCAGCAACATAAGAAGGGTTGGGTCATGGGGCCAGGATGCTTTTGTAATGG g n l | t i I 458957840/166-649 TGATCTTGGGCGGCAACATGAGAAGGGTTGGGTCATGGGGCCAGGATGCTTTTCTAAAGG casel9h/l-150 TGATCCTGGGCAGCAACATAAGAAGGGTTGGGTCGTGGGGCCAGGATGCTTTTGTAATGG casel9c/l-504 AGTCTTCTCCAAAAGAAGCATGAGCCTGAGGAAAAGAAAAGCCCCTTTTAGGCCAGGCAC gnl|ti|458957840/166-649 GGTCTTCTCCAAAAGAAGCATGAGCCTGAGGAAAAGAAAAGTCCCCTCTAGGCCAGGCGC casel9h/l-150 AGTCTTCTCCAAAAG casel9c/l-504 TGTGGCTCATGCCTTTAATCCCAGCACTTTGGGAAACCCAGGTGGGCGGATCACCTGAGG g n l | t i I 458957840/166-649 GGTGGATCATGCCTTTAATCCCAGCACTTTGAGAAACCCAGGTGGGCAGATCACCTCAGG casel9h/l-150 casel9c/l-504 TCAGGAGTTCGAGACAAAACTGGCCAACGTGGCAAAACCTCATCTCTACTAAAAATACAA gnl|ti|458957840/166-649 TCAGGAGTTCCAGACCAAACTGGCCAACATGGCAAAACCTCATCTTTACTAAAAATACAA casel9h/l-150 casel9c/l-504 AAATTAAGCGGGCATGGTGGCTTATGCTGGTAAACCCAGCTACTCGGGAGGCTGATGCAT g n l | t i I 458957840/166-649 AAATTAACCGGGCATGATGGCTCATGTCGGTAAACGCAGCTACTCGGGAGGCTGACGCAT casel9h/l-150 casel9c/l-504 GAGAATCGCGTGAACCAGGGTGGCAGAGGCTGCAGTGAGCCGAGAACATGCCACAGCACT gnl|ti|458957840/166-649 GAGAATCGCTTGTACCAGGGTGGCGGAGTTTGCAGTGAGCCGTGAACACGCCACTGCACT casel9h/l-150 casel9c/l-504 CCAGGCTGGGCCACAGAGTGAGACTCCATCTGAAAAAAAAAAAAAAAGAAAAAGAAAAAG gnl|ti|458957840/166-649 CCAGCCTGGGCGACAGAGTGAGACTCCGTCTGAAAAAAAAAAAA casel9h/l-150 casel9c/l-504 AAAAAAAAGCCCCCTCTAGCATAAACTTATTTCAGAAATAACACTAGTGAACAAGTAACC gnl|ti|458957840/166-649 AAAAGCCCCCTCTAGCGTAAACTTATTTCAGAAATAACACTAGCGAACAAGTAACC casel9h/l-150 CCCCCTCTAGCATAAACTTATTTCAGAAATAACACTAGTGAACAAGTAACC easel9c/l-504 CTTTCCAAATTATTTTGAATCTAA gnl|ti|458957840/166-649 CTTTCCACATTATTTTGAATCTAA case19h/l-150 CTTTCCAAATTATTTTGAATCTAA chr5 = 29115431:scaffold_3707 8:3005315:3005552:-... i m p r e c i s e . d e l e t i o n of HAL1 fragment i n human, no f l a n k i n g i d e n t i t y CLUSTAL case20c/1-337 AATACTGAAGAGACTGTCAGTGAGGCCCCTCCTTAATGCACCATTCCTATCAACTTTTGC gnl|ti|509178888/301-662 AATACTGAAGAGACTATCAGTGAGGCCTCTCCTTTATGCACCATTCCTGTCAACATTCGT case2Oh/1-100 AATACTGAAGAGACTGTCAGTGAGGCCCCTCCTTAATGCACCATTCCTAT case20c/1-337 TCTTTGGAAACAATAACAGAAAACAGAAAGTTAATGAAAATATTGACTCCATGATATAAA g n l | t i I 509178888/301-662 TCTTTGGAAACAATAATGGAAAACAGAAAGTTAATGAAAATATTGACTCTATGATATAAA case20h/l-100 case20c/1-337 GCAGGATACTATAAAAAGGGATATTTAAAGAAAAAA-TAGAAATTAAAAACATGATTGT-gnl|ti|509178888/301-662 GCAGGATACTATAAAAAGGGATATTTAGAGAAAAAAATGGAAATTAAAAACATGATAGTT case20h/l-100 case20c/l-337 GAT AT ATATATATAT AT AT AT AT AT AT TTGAATGTTT gnl | t i | 509178888/301-662 TTATAAATATATATATATATAAATATATATATATATAAATATATATAATTTTGAATGTTT 151 case20h/l-100 case20c/l-337 GGAAGACAAAGTTGTAGACATAACTTAGAGAGTCAGAGACGTGGAGAATAGAAGACAAAG gnl|ti|509178888/301-662 GGAAGACAAAGTTGTGGACATAACTTAGAGAGTGAGAGACATGGAGAACAGAAGACAAAG case20h/l-100 case20c/l-337 GGAGGAGCAACTGAACAGATTAAGTATAAACATATACATTGTTTCCAAAAAGAAAACAGT gnl|ti|509178888/301-662 GGAGGACCAACTGACCACATTAAGTATAAAGATATAGATTGCTTCCAAAAAGAAGACAGT case2 Oh/1-100 GAACAGATTACGCATAAACCTATACATTGTTTCCAAAAAGAAAACAGT case20c/l-337 GT gnl]ti|509178888/301-662 GT case20h/l-100 GT chr5:169226842:scaffold_37615:12572677:12572918:+ ...imprecise d e l e t i o n of a MIRb element, 3 bp i d e n t i t y f l a n k i n g the d e l e t i o n , probably blunt-end d e l e t i o n CLUSTAL case21c/l-341 g n l | t i I 572959929/194-536 case21h/l-100 case21c/l-341 gnl|ti|57295992 9/194-536 case21h/l-100 case21c/l-341 gnl|ti|57295992 9/194-536 case21h/l-100 case21c/l-341 gnl|ti|572959929/194-536 case21h/l-100 case21c/l-341 gnl|ti|572959929/194-536 case21h/l-100 TTACGTACCCTTTGATGAAGTATAAGCAAAAAGTTTATATTTGGACAAATTAAATTCTGG TTACGTACCCTTTAATGAAGTATAAGCAAAAAGTTTAGATTTGGACAAATTAAATTCTGG TTACGTACCCTTTGATGAAGTATAAGCAAAAAGTTTATATTTGGACAAAT CCCTGCCACTAACTTGCTCTGTAGCCTGAGTTTACTTATTTCAACTCACATAAGCCTCAA CCCTGCCACTAACTTGCTCTGTAGCCTGAGTTTACTTATTTCAACTCATATAAGCCTCAG TTTGCTCATCAGTAACATGGAGATGATAACACCTTACTCAAAGAATTGTGGTAGAAATAA TTTGCTCAACAGTAACATGGAGATGATAACAGCTTACTCAAAGAATTGTGGTAGAAATAA ACTGACTTCTGAATATAAAGTGCTTAGCACAGAGTTGGGCTTATAGCA TTCATTAA ACTGACTTCTGAATATAAAGGGCTTAGGACAGAGTTGGGCTTATAGCAAGCATTCATTAA CATGAATAACATTATGTCAGTATTTTTAAAACAAGTACCCACCATGAATTAGAATATAAA CATGAATAACATTATGTCAATATTTTTAAAACAAGTATCCACCATGAATTATAATATAAA ATAAA case21c/l-341 gnl|ti|572 95992 9/194-536 case21h/l-100 G T A T G C C T G A A T A A T T A A G A T G A A A C A T A A G A C T G A A T T C A A A T A G T A T G C A T G A A T A A T T A A G A T A A A A C A T A A G A C T G A A T T C A A A T A G T A T G C A T G A A T A A T T A A G A T G A A A C A T A A G A C T G A A T T C A A A T A chr5:17 6660475:17 6660732:scaffold_34495:399572 :-...precise d e l e t i o n of AluJo i n chimpanzee CLUSTAL case22h/l-387 CCTGATTTCTTCACTGTTTACATGCTGTAACATCTACACATCATGCTAAGAAAAAAAAAA gnl | t i I 537031087/370-730 CCTGAGTTCTTCACTGTTTACATGCTGTAACATCTACATATCATGCTTAAAAAAAAAAAA case22c/1-130 CCTGATTTCTTCACTGTTTACATGCTGTAACATCTACACATCATGCTAAGAAAAAAAAAA case22h/l-387 AAAAAAAGGAGAGAGAGAGCGAGAGAAC ACTTTCC AGCCTGGGC AAC AT AGTAAGACCCC gnl|ti|537031087/370-730 GAGAGA—GAGAGAGAGAGTGAGAGAACACTTTCCAGCCTGGGCAACATAGTTAAGACCC case22c/l-130 AAAAA case22h/l-387 CTTTCTCAACAAAAAATAAAAAAA-ATTGCCCACGCATGGTGGCAAGTGGCTGCAGTCCC gnl|ti|537031087/370-730 CCATCTCAATAAAAAATAAAAAAATATTACCCATGCATGGTGGCAAGTGGCTGTAGTCCC case22c/l-130 case22h/1-387 AGCTACTTGGGAAGCTGAGTTGGGAGGATTGCTTGAGCCCAGGAGCTCAAGACTACAATG gnl | t i | 537031087/370-730 "AGCTACTTGGGAAGCTGA TTGCTTGAGCCCAGGAGCTCAAGACTACAATG case22c/l-130 case22h/l-387 AGCTATGATCACGCCACTGTACTCAAACCTGGACAACAAGACCTCATCTCTTATTAAAAA 152 g n l | t i I 537031087/370-730 AGCTACGATCACGCCACTGCACTCCAACCTGGACAA GACCTCATCTCTTATTTAAAA case22c/l-130 case22h/l-387 AAAAAAAAAAAAAAAAAAAAAAAGAACACTTTACTTTAGCGCAGCTTTATGAAGTGCTTT gnl|ti|537031087/370-730 AC AAAAAAAAAAGAACACTTTACTT-AGCACAGCTTTATGAAGTGCTTT case22c/l-130 GAACACTTTACTTTAGCACAGCTTTATGAAGTGCTTT case22h/l-387 ACCAGCTGGTCTCAGCTGACTATTCCTA gnl|ti|537031087/370-730 ACCAGCTGGTCTCAGCTGACTATCCCTA case22c/1-130 ACCAGCTGGTCTCAGCTGACTAGTCCTA chr6:12 9040862:scaffold_37501:5172375:5172 650:-...bad match.... chimpanzee and rhesus l o c i do not match >case23c TAAGAAATACATCGAGAATATAAAAAGATAATTTAAACATCCTGAAAATA TTGGGAGGCCGAGACGGGCGGATCACGAGGTCAGGAGATCGAGACCATCT TGGCTAACACGGTGAAACCCCGTTTCTACTAAAAATACAAAAAATTAGCC GGGCGTG.TTGGCGGGCGCCTGTAGTCCCAGCTACTTGGGAGGCTGAGGCA GGAGAATGGCATGAACCTGGGAGGCGGAGCTTGCAGTGAGCCGAGATCGC GCCACTGCACTCCAACCTGGGAGACACAGCGAGACTCCGTCTCAAAAAAA AAAAAAAAAAAACATCCTGAAAATAAGAAATAATGCCATTAAAAGAAAAT TCAATACATATGATTAATATAAAAA >case23h TAAGAAATACATCGAGAATATAAAAAGATAATTTAAACATCCTGAAAATA AGAAATAATGCCATTAAAATAAAATTCAATACATATGATTAATATAAAAA >gnl|ti I 540771525 NNNAAAACCTTTATCNNNNNGTGGGCCCGCGTTGTCATCAGATGGGGGGG CTCATAACACTCGTTCCAGCTACCCAGGTGTTTAGGTCGGAGAATCACCT AAGCCCAGGTGGTCATGGCTGCACCGAGTCACGATCGCATCACCGCATTC GAAGCCTGGGTGACAGAGTGAGACCCCGTCTGGGGGTAAAAAAAAAAAAA AGTAAGTAAGTAAAGTAAAGTAGTGAAGTAAAGAAAAAAAATAGAGAATC TTAAGAAATCCATCGAGAATATAGAAAGATCGTTTTAAAATAAAAACAAT GCCATTAAGGGAGGAGACCACCCCTCATATCATCTTATGCCCAAGTTCTG CCTCCAAAGAATGAAGAAGTAAAAACTAAAAGGCAGAAATGAAGTCTACA GGCAGACAGCCCGGCGCTGCACCCTGGGCCTGGTAGTTAAAGATCTATCT AATCGGTTCTGTTATCTGTAGATTACAGACATTGTATAGAAATGCACTGT GAAAATTCCTATCTTGTTTTGTTCCAATTACCGGTGCATGCAGCCCCCAG TCACGTACCCCCTCCTTGCTCAATCAATCATGACCCTCTCACATGCACCC CCTCAGAGTTGGGAGCCCTTAAAAGGGACAGGAATTGCTCACTCAGGGGG CTGGGCTCTTGAGACAGGAGTCTTGTGGACACCCCCAGCCGAATAAACCC CTTCCTTCTTTAACTTGGTGTCTGAGGGGTTTTGTCTGCAGCTCATCATG CTATACCATTAAAATAATATTCAATACATATGATTAATATAAAAATGGTA ACAACTACAGAATGACTAGGGAGATGACATAAGGATGGAACTCATCTTGC ATACAGTTCAGAGAAGCTAGAATAAACATAGAAATGTAATTGAGAATATA GAAGGTAAGGTTGAAAGCTAAAACTCTTTCTTNATGNNGAAGACTGGTAG AGATAGAATATTTGAGCGATACTGCTTTGAGATGCTCCAGAATTTTCATG GGTTCCCATCTGTGNTTTCCCTTATGCTAGNCACTGCGTTTCAAAATTAA ATGGAAATTCCNGAATAAAATTCNTTTTAATTTGTTAGGAATACTGCTCC AAACAGGGTTCCCTTATTCTGTTCCCACCAAAAAGGGTTCAAAATCTGTT GTAAAAAAAAGGTTTCAATATCTGTTTCATAAAAAGGTGGGGGCTGTTTT TTATTTAATCACAATCGGAAGTAAAAACAAGTTTCCTGACTTCACAATAA AAAGAAGCTCGCCCCTTTTCTTTTTTTTTTTTTTTACCCCCACGCCCAAA AATTTATGGTTTGTTATTATTAAATTNNNNNNNNNNNNNNNNNNNNTTTT ATTTTTTTTTAACCACAAAAAAAAAACAACCTTTTTTTTTTTTTTTNNNN NNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNCCCCNN NNNT chr7:5779663:scaffold_37557:3099237:3099555:+ ...precise d e l e t i o n of AluSg i n human CLUSTAL case24c/l-468 TGAACTGCAACTGTGATACTTATTAGCATGTCACCTGGTGTTTTGTTTTCATTTCACTTT gnl|ti|567316288/263-732 TGCACTGCAATAGTGATACTTATCAGCACGTCACCTGGGGTTTTGTTTTCATTTCACTTT 153 case24h/l-150 TGAACTGCAATAGTGATCCTTATCAGCATGTCACCTGGTGTTTTGTTTTCATTTCACTTT case24c/l-4 68 AAGAATGTGCCATGTTGGCCGGGTGTGGTGGCTCACGCCTGTAATCCCAGCACTTTGGGA gnl|ti|567316288/263-732 AAGAATGTGCCATGTTGGCCGGGCGTGGTGGCTCATGCCTGTAATCCCAGCACTTTGGGA case24h/l-150 AAGAATGTGCCATGT case24c/l-4 68 GGCCGAGGCGGGAGGATCACAAGGTCAGGAGTTTGAAACCAGCCTGACCAACATAGTGAA gnl|ti|567316288/263-732 GGCCGAGGCGGGCGGATAACAAGGTCACAAGTTCAAAACCTGCCTGACCAACATGGTGAA case24h/l-150 case24c/l-468 ACTCCATCTCTACTAAAAATACAAAAAAATAAAAAATTAGCCAGACATGGTGGCGCATGC gnl|ti|567316288/263-732 ACACCATCTCTACTAAATATACAAA AAAAGTCAGCCAGGCGTGGTGGCGCATGC case24h/l-150 case24c/l-4 68 CTGTAATCCCAGCTACTCTGGAGGCTGAGGCAGGAGAATCGCTTGAACCTGGGAGGCAGA gnl|ti|567316288/263-732 CTGTAATCGCAGCTACTGGGGAGGCTGAGGCAGGAGAATCGCTTGAACCTGGGAGATGGA case24h/l-150 case24c/l-468 GGTTGCAGTGAGCCGAGATCGTGCCATTGCACTCCAGCCTGGGCAATGAAAGTGAAACTC g n l | t i I 567316288/263-732 GGTTGCAGTGAGCCGAGATCGTGCCATTGCACTCCAGCCTGGGCAATAAGAGTGAAACTC case24h/l-150 case24c/l-4 68 CATCTCAAAAAAAAAAAG AAGAATGTGCCGTGTGATCGTATTTCTAATCCCT g n l I t i I 567316288/263-732 CATCTCAAAAAAAAAAAAAAAAAAAAAAGAATTTGCCATGTGATCGTATTTCTAATCCTT case2 4h/1-150 GATCGTATTTCTAATCCCT case24c/l-468 TTCACTCTGGAATCCTGCTCTTACCATATTAATGTTGATTAGCATCTCAGGTTTCA g n l | t i I 567316288/263-732 TTCACTCTGGAATCCTGTCCTCACCATATTAATGTTGAATAGCATCTCAGGTTTCA case24h/1-150 TTCACTCTGGAATCCTGCCCTTACCATATTAATGTTGAATAGCATCTCAGGTTTCA chr7:24969020:scaffold_36484:641689:641996:+ ...precise d e l e t i o n of AluSc i n human: 2 of these s i t e s i n human and chimpanzee genomes both f i l l e d w ith AluSc i n chimpanzee, one empty and one f i l l e d s i t e i n human CLUSTAL case25c/l-461 AGGCCCGTTCTGTGTCCGGAGGGGCTGTGATCCTATCAGGACAGGAATCCAGCTCGGAGC g n l | t i I 541662238/247-704 AGGCCCGTTCTGTGTCCGGAGGGGCTGTGATCTTATCAGGACAGGAATGCAGCTCGGATC case25h/l-150 TGGCCTGTTCTGTGTCCAGAGGGACTGTGA TCAGGACAGGAACCCAGCTCGGAGC case25c/l-461 TCCTATTA-AAGATGACTGTTGGCCGGGTGCAGTGGCTCCCGCCTGTAATCCCAGCACTT g n l | t i I 541662238/247-704 TCCTGTGGTAAGATGACTGTTGGCCGG-TGCGGTGGCTCCCGCCTGTAATCCCAGCACTT case25h/l-150 TCCTGTGATAAGATGACTGTT case25c/l-461 CAGGAGGTCGAAGCGGGCAGATCATGAGGTCAAGAGATCGAGACCGTCATGGCCAACATC gnl|ti|541662238/247-704 CAGGAGGCCGATGAGGGCAGATCACAAGGTCAAGAGATTGAGACCATCATGGCCAACATG case25h/l-150 case25c/l-461 GTGAAACCCCGTCTCTACTAAAAATACAAAAATTAGCTGGGTGTGGTGGCAGGCACCTGT gnl|ti|541662238/247-704 GTGAAACCCCGTCTCCACTGAAAATAGAAAAATTAGCTGGATGTGGTGGCAGGCGCCTGT case25h/l-150 case25c/l-4 61 AGTCACAGCTATTTGGGAGGCTGAGGCAGGAGAATCGCTTGAACCCAGGAGGTGGAGGTT gnl|ti|541662238/247-704 AGTCCCAGAAACTTGGGAGGCCAAGGCAGGAGAAACGCTTAAACCTGGGAGGTGGAGGTT case25h/l-150 case25c/l-461 GCAGTGAGCCAAGATCGCGCCACTGCACTCCAGCCTGGTGACAGAACGAGACTACGTCTA gnl|ti|541662238/247-704 GCAGTGAGCCAAGATTGCGCCACTGTACTCCAGCCTGGTGACAGAATGAGACTCCATCTC case25h/l-150 : case25c/l-4 61 AAAAAAAAAAAAAAAAAAAAAGACTGTAGATACTAATATAAACCCCACCTTCCCCAAATC gnl | t i I 541662238/247-704 AAAAAAAAAAAAAAGAT GACTGTTGATATTAATATAAACCCCACCTTCCCAAAATT case25h/l-150 GATATTAATATAAACCCCACCTTCCAAAAACC case25c/l-4 61 TGTTTATCCTGATCTTAAGATACGGC-ACATGTTAATGAGTTG gnl|ti|541662238/247-704 TATTTATCCTGATCTTAAGATATGGCTACGTGTTAAAGAGTGG case25h/l-150 TATTTATCCTAATCCTAAGATAAGAC-ACATTTTAATGAGTTT 154 chr7:128710174:scaffold_37671:707170:707496 :-...precise d e l e t i o n of AluSx i n human CLUSTAL case2 6c/l-476 TTGCTGTGAAGCTATGGGGGCTTTTTATGAGGAAGGCTCTATGCAAGGGTGAGGATGGAA gnl|ti|513419099/206-664 TTGCTGTGAAACTATGGGGGCTTTTTGTGAGGAAGGCTCTATGCAAGGGAGAGGATGGAT case2 6h/1-150 TTGCTGTGAAGCTATGGGGGCTTTTTATGAGGAAGGCTCTATGCAAGGGTGAGGATGGAT case26c/l-476 ATGGGGTTTGATGGTTAGAAAGTGGGAGAGAAGGCCAGGTGCAGTGGCTCACACCTGTAT gnl|ti|513419099/206-664 ACGGGACTTGATGGTTAGAAAGTGGGAGAGAAGTCCAGGTGCAGTGGCTCACACCTGTAA case26h/l-150 ATGGGGCTTGATGGTTAGAAAGTGGGAGAGAA case26c/l-476 TCCCAGCACTTTGGGAGGCCGAAGTGGGTGGATCACCTGAAGTCAGGAGTTCAAGACCAG gnl Iti|513419099/206-664 TCCCAGCACTTTGGGAGGCCAAAATGGGTGGATCACCTGAGGTCAAGAGTTCGAGACCAG case26h/l-150 case2 6c/l-47 6 CCTGGCCAACATGGTGAAACCCTGTCTCTACTAAAAATAAAAAAATTAGCCGGGCATGGC gnl|ti|513419099/206-664 CCTGGCCAATGTGGTAAAACCCCGTCTCTCCTAAAAATAAAAAAATTAGCTGGGCATGGT case26h/l-150 case26c/l-476 GGCGTACACCTGTAATCCCAGCTACTCGGAAGGCCGAGGC AGAAGAATTGCTTGTAC gnl|ti|513419099/206-664 GGCAGGCGCCTGTAGTCCCAGCTACTCGGGAGGCCAAGGCCAAGGGAGAATGGATTGAAC case26h/l-150 case2 6c/l-47 6 CTGGGAGGTAGATGTTGCAGTGAGCCAAGATTGCACCATTGCACTCCAGCCTGGGTGACA gnl|ti|513419099/206-664 CTGGGAGCTTGAGCTTGCAGTGAGCCAAGATCACGCCACTGTACTCCAGCCTGGGTGACA case26h/l-150 case2 6c/l-47 6 GGGGGAGACTCCGTCTCAAAAAAAAAAAAAAAAAGAAAAAGAAAAAGAAAGTGGGAGAGA gnl | t i | 513419099/206-664 GAGTGAGACT--ATCTCAAAAAAAAAAAAAAA GTGGGAGAGA case26h/l-150 case2 6c/l-47 6 AGGGAACAGTGACTGCAGGAATAGAAAAAATGTCCACAGAGGAGGAATGAGGACATGGC gnl|ti|513419099/206-664 AGGGAACGGTGACTACAGGAATAGAAAAAGTGTCCACTGAGGAGGAAGGAGGACTTGGC case2 6h/l-150 -GGGAACGGTGACTGCAGGAATAGAAAAAATGTCCACAGAGGAGGAAGGAGGACATGGC chr7:132523884:132524216:scaffold_32923:964569:-...AluY i n Rhesus, gene conversion to AluYb9 i n human, p r e c i s e d e l e t i o n i n chimpanzee CLUSTAL case27h/l-500 TTACTACAGAAATTATGGGAAATGCTTACTTTTTAAAAGGAGAAAGGGAAAGAATCTCAT g n l I t i I 496205884/177-647 TTACTGCAGAAATTGTGGGAAATGCTTACTTTTTAAAAGGAGAAAGGGAAAGAATCTCAT case27c/l-168 TTACTACAGAATTTGTGGGAAATGCTTACTTTTTAAAAGGAGAAAGGGAAAGAATCTCAT case27h/l-500 GTTGAAAATTGTCATTAGGTAAAGTAATAGAATTAATGGAGCAGGCCGGGCGCGGTGGCT gnl | t i | 496205884/177-647 GTTGAAAATTATC GCGGTGGCT case27c/l-168 GTTGAAAATTGTCATTAGGTAAAGTAATAGAATTAATGGAGCA case27h/l-500 CACGCCTGTAATCCCAGCACTTTGGGAGGCCGAGGCGGGTGGATCATGAGGTCAGGAGAT gnl|ti|496205884/177-647 CAAGCCTGTAATCCCAGCACTTTGGGAGGCCGAGATGGGCGGATCACGAGCTCAGGAGAT case27c/l-168 case27h/l-500 CGAGACCATCCTGGCTAACAAGGTGAAACCCCGTCTCTACTAA-AAATACAAAAAATTAG g n l I t i I 496205884/177-647 CGAGACCATCCTGGCTAACACGGTGAAACCCCGTCTTTATTAAGAAATACAAAAAAT-AG case27c/l-168 case27h/l-500 CCGGGCGCGGTGGCGGGCGCCTGTAGTCCCAGCTACTGGGGAGGCTGAGGCAGGAGAATG gnl|ti|496205884/177-647 CCGGGCGAGGTGGCAG-CGCCTGTAGTCCCAGCTACTCGGGAGACTGAGGCCGGAGAATG case27c/l-168 •-case27h/l-500 GCGTTGAACCCGGGAAGCGGAGCTTGCAGTGAGCCGAGATTGCGCCACTGCAGTCCGCAG g n l | t i I 496205884/177-647 GCAT-GAACCCGGGAGGCGGAGCTTGCAGTGAGCTGAGATCCGGCCACTGCACTCC case27c/l-168 155 case27h/l-500 TCCAGCCTGGGCGACAGAGCGAGACTCCGTCTCAAAAAAAAAAAAAAAAAAAAAAAAA— g n l | t i I 496205884/177-647 -—AGCCTGGGCTACAGAGCGAGACTCCGTCTCAAAAAAAAAAAAAAAAAAAAAGAAAAT case27c/l-168 case27h/l-500 AATAGAATTAATGGAGCAATCCAAAATGAGCTAAATAAGTTTCT gnl|ti|496205884/177-647 TATCACTAGGTAAAGTAATAGAATTAACGGAGCAATTCAAAATGAGCTAAATAAGTTTCT case27c/l-168 ATCCAAAATGAGCTAAATAAGTTTCT case27h/l-500 TTGTGAGAATTCTTCTAGAGATTAATTCTAGAATTCTTC gnl|ti|496205884/177-647 TTGTGAGAATTCTTTTAGAGATTAATTCTAGAATTCTTC case27c/l-168 TTGTGAGAATTCTTCTAGAGATTAATTCCAGAATTCTTC chr9:32249992:scaffold_37419: 6540548:6540685:-...imprecise d e l e t i o n of a MIRb element i n human, no f l a n k i n g i d e n t i t y CLUSTAL case28c/l-237 CTCCTTAAAGGAAAGTGAATGTGAACTGAAGTCTAGACCAACACC-TTATGCACAGTCTA g n l | t i I 511659877/91-328 CTCCTTAAAAGAAAGGAAATGTGAACTGAAGTTGAGAACGACACCCTTATGCACAGTATA case28h/l-100 CTCCTTAAAGGAAAGTGAATGTGAACTGAAGTCTAGACCAACACCTT case28c/l-237 AGAGGAAAGAATATGAGACTGAAGCTATTGAGGACTGGGTTTAAGTCACTATCCTATTAT gnl | t i | 511659877/91-328 AGAGGAAAGAATATGAGACTGAAGCTGTTGAGGACTGGATTTAAGTCACTATCCCATTAT case28h/l-100 case28c/l-237 TTACTATCTTTGCAATCTAGGATAAAGTACTTAACTCCCCTGAACCTTGGATCCTGAAAC gnl Iti|511659877/91-328 TTACTATCTTTGCAATCTAGGACAAAGTACTTAACTCCCCTGAACCTTGGATTCTGAAAC case28h/l-100 case28c/l-237 CACACATGGGAAGACATTGTTACCTTTGTAGCACAGGATTGATGTGTTAACAAATGGG gnl|ti|511659877/91-328 TATACATGGGAAGACACTGTTACCTTTGTAGCACAGGATTGAGGTGTTAACAAATGGG case28h/1-100 ATGGGAAGACATTGTTACCTTTGTAGCACAGGATTGATGTGTTAACAAATGGG chr9:677288 61:67729179:scaffold_34695:1245496:+ . . . i n v e r s i o n of AluY i n Rhesus, gene conversion to AluYb8 i n human, p r e c i s e d e l e t i o n i n chimpanzee CLUSTAL case29h/l-479 CTTTCTACC-CACTTAACAGACTTGTCTTCTCTTCCCCATGGGAATAAAATTTTAGGCAG g n l I t i I 556286157/11-486 GATGGTAAGTAGTTCATC—ACTTGTCTTCTCTTCACCATTGGAATAAAATTTTAGGCAG case29c/l-161 CTTTCTACC-CACTTAACAGACTTGTCTTCTCTTCCCCATGGGAATAAAATTTTAGGCAG case29h/l-47 9 GTCTCTTAGATCTCCCGGTTA GGCCGGGCGCGGTGGCTCACGCCTGTAATCCCAGC g n l | t i I 556286157/11-486 GTCTCTCAGATCTCCTGGTTATTXXGGCTGGGCGTGGTGGCTCATGCCTGTAATCCCAGC case29c/l-161 GTCTCTTAGATCTCCTGGTTATT case2 9h/l-47 9 ACCTTGGGAGGCCGAGGCGGGTGGATCATGAGGTCAGGAGATCGAGACCATCCTGGCTAA gnl|ti|556286157/ll-486 CCTTTGGGAGGCCAAGGGGGGCGGATCACAAGGTCAGGAGATGGAGAGCATCCTGGCTAA case29c/l-161 case2 9h/l-47 9 CACGGTGAAACCCCGTCTCTACTAAAAATACAAAAAATTAGCCGGGCGCGGTGGCGGGCG gnl|ti|556286157/11-486 CACAGTGAAACCCTATCTGTACTAAAAATACAAAAAATTAGCTGGGCATGGTGGTGGGCG case29c/l-161 case2 9h/l-479 CCTGTAGTCCCAGCTACTCGGGAGGCTGAGGCAGGAGAATGGCGTGAACCCGGGAAGCGG g n l | t i I 556286157/11-486 CCTGTAGTCCCAGCTACTGGGGAGGCTGAGGCAGGAGAATGGCATGAACCCAGGAGGCAG case29c/l-161 case29h/l-47 9 AGCTTGCAGTGAGCCAAGACAGCGCCACTGCAGTCCGCAGTCCGGCCTGGGCGACAGAGC gnl|ti|556286157/11-486 AGCTTGCAGTGAACCGAGATCACGCCACTATAC CACTCCAGCCTCGGCGAAACAGC case29c/l-161 case29h/l-479 GAGACTCCGTCTCAAAAAAAAAAAAAAAAAGAT—CTCCCGGTTATTCTTAAGTGGTGAA gnl | t i | 556286157/11-486 AAGACTCGGTCTCAAAATAATAATAATAATGATXXCT GGTTAGTCTTAAGTGGTGAA case29c/l-161 CTTAAGTGATGAA 156 case29h/l-479 AAGTTTGACTACTAGTCACATAATACATCCAATGTGATAATAAATAACTCAAATTCTCAT gnl Iti|556286157/11-486 GAGTTTGACTACTAGTCACATAATACATCCAGTATAATAATAAA-AACTCAAATTCTCAT case29c/l-161 AAGTTTGACTACTAGTCACATAATACATCCAATGTGATAATAAATAACTCAAATTCTCAT case29h/l-479 CTAATA gnl|ti|556286157/11-486 CTAATA case29c/l-161 CTAATA chr9:84428070:84 428205:scaffold_36211:2258065:-...precise d e l e t i o n of an AluSg/x fragment i n chimpanzee CLUSTAL -Alu boundary shown by 1 | ' case30h/l-306 AGTAAGACTCTGTCTCAAAAAAAAAAAA— - TTAAATCCTTAGAAAGA gnl|ti|542095096/367-694 AGTAGGATTCTGTCTCAAAAAAAAAAAAAAAAAAAAAAAAAATTTAAATCCTTAGAAAGA case30c/l-173 AGTGAGACTCTGTCTCAAAAAAAAAAAAA ATTAAATCCTTAGAAAGA case30h/l-306 TGTATCCTCTGCTGCTGCTCTAGAACTCTAGGT|GGAGGCAAAGGTTGCAGCCAGCGGAGA gnl|ti|542095096/367-694 TGTATCCTCTGCTGCTACTCTAGAACTCTAGGT|GGAGGCGGAGGTTGCAGTGAGTGGAGA case30c/l-173 TGTATCCTCTGCTGCTGCTCTAGAACTCTAGAT|GGAGGCAGA case3Oh/1-306 TCATGCCACTGCACTCCAGCCTGGGCAACAGAGTGGCACTCCATCTCAAAAAAAAAAAAA gnl | t i | 542095096/367-694 TCATGCCACTGCCCTCCAGCCTGGGCAACAGAGTGACACTCCATCTCAAAAAAAAAAAAA case30c/l-173 case30h/l-306 AAATCCTTAAAAGTATGTATCCTCTGCTGCTACTCTAGAACTCTAGGTGGAGG gnl|ti|542095096/367-694 TGTATTCAAATCCTTAAAAAGATGTGTCCTCTACTGCTACTCTAGAACTCTAGGTGGAGG case30c/l-173 case30h/l-306 CAGATTTCTAAACCAGTTCTTTTGCACAGGAATTACTGGTTTGGGTGGGGCGTGGTGACG gnl|ti|542095096/367-694 CAGATTTCTAAACCAGTTCTTTTGTACAGGAATTACTGGTTTGGGTGGGGCGTAGTGACG case30c/l-173 TTTCTAAACCAGTTCTTTTGCACAGGAATTACTGGTTTGGGTGGGGCGTGGTGACG case30h/l-306 CTGCTGTCTCAGAATTAATGTAATCATG g n l | t i I 542095096/367-694 CTGCTGTCTCAGAATTAATGTAATCATG case30c/l-173 CTGCTGTCTCAGAATTAATGTAATCATG chrlO:35597212:35597542:scaffold_37564:16236237:+ ...independent i n s e r t i o n s of AluYa5 i n human and L1PA5 i n Rhesus CLUSTAL case31h/l-430 AAACCTGCAATATGCTAACCAAACCACTTTTAATTAAAAGGAGAAAAAAGGCCGGGAGCG case31c/l-100 AAACCTGCAATATGCTAACCAAACCACTTTTAATTAAAAGAAGAAAAAA g n l | t i I 470892232/187-735 AAACCTGCAATATGCTAACAAAACCACTTTTAATTAAAAGAA case31h/l-430 GTGGCTCACGCCTGTAATCCCAGCACTTTGGGAGGCCGAGGCGGGCGGATCACGAGGTCA case31c/l-100 g n l | t i I 470892232/187-735 TATTGCGGCACTATTCACAATAGCAAAGACTTGGAACCAACCCAAATGTCCA case31h/l-430 AGAGATCGAGACCATCCC-GGCTAAAACGGTGAAACCCCGTCTCTACTAAAAATACAAAA case31c/l-100 g n l | t i I 470892232/187-735 TCAATGATAGACTGGATTAAGAAAATGTGGCACATATACACCATGGAGTACTGTGCAGCC case31h/l-430 AAATTAGCCGGGCGTAGTGGCGGGCGCCTGTAGTCCCAGCTACTTGGGAGGCTGAGGCAG case31c/l-100 g n l | t i I 470892232/187-735 ATAGAAAAGGATGAGTTCATGTCCTTTGTAGGGACATGGATGAAGCTGGAAACCATCATT case31h/l-430 GAGAATGGCGTGAACCCGGGAGGCGGAGCTTGCAGTGAGCCGAGATCCCGCCACTGCACT case31c/l-100 g n l | t i I 470892232/187-735 CTGAGCAAACTATCACAAGGACAGAAAACCAAACACTGCATGTTCTCACTCATAGGTGTG case31h/l-430 CCAGCCTGGGCGACAGAGCGAGACTCCGT-CTCAAAAAAAAATAAAAAATAAAAAAAAAA case31c/l-100 157 g n l | t i l 4708 92232/187-735 AATCGAACAATGAGAACACTTGGACACAGGAAGGGGAACATCACACACCAGGGCATGTCG case31h/l-430 AAAAAAT case31c/l-100 g n l | t i I 470892232/187-735 GGGTGGGGGGGATAGCATTAGGAGATATACCTAATGTAAATGACGAGTTAATGGGTGCAG case31h/l-430 case31c/l-100 gnl|ti|470892232/187-735 CACACTAATATGGCACATGTATACATATGTAACAAACCTGCAGGTTGTGCACATGTACCC case31h/l-430 AAAAGGAGAAAAAAGCCTTTTCAAGATCTT case31c/l-100 GCCTTTTCAAGAACTT gnl | t i I 470892232/187-735 TAGAACTTAAAGTATAATAATTAAAAAAAAAGAAGAAGAAAAAAGCCTTTTCAAGAATTT case31h/l-430 ACAACGGCTCTTATTAGATTATAAATTGTAACCTC case31c/l-100 ACAATGGCTCTTATTAGATTATAAATTGTAACCTC gnl|ti|470892232/187-735 ACAATGGCTCTTATTAGATTATAAAGTGTAACTTC c h r l l : 82826588:scaffold_37428:2205199 = TSD discernable, imprecise d e l e t i o n of L1PA13 element i n human, 2 bp f l a n k i n g i d e n t i t y , probably blunt-end d e l e t i o n CLUSTAL case32c/l-402 TGCAGCAGAATTTATGAGGTAGTGATTATTATGTTAAGTGCAAGAACT-GAAGTGGGAGC g n l | t i I 529982443/82-484 TGCAGAAAAAGGTATGAGGTAGTGATTATTATGTTAAGTGCAAGAATTAGAAGTGAGAGT case32h/l-100 TGCAGCAGAATTTATGAGGTAGTGATTATTATGTTAAGTGCAAGAACT-GAAG case32c/l-402 TAAATGATGAGAACACCTGGACACATAGAGGTGAACAACACACACTGGGGCCTATTGGAG gnl|ti|529982443/82-484 TAAATGATGAGAACACATGGACACATAGAGGGGAGCAACACACACTGGGGCCTGTTGGAG case32h/l-100 : case32c/l-402 GGTAAAGAGTAGGAGGAGGGAAAGGATCAGGAAAAATAGCTAATGGGTACTAGGCTTAAC gnl|ti|529982443/82-484 GGTAAAGAGTAGGAGGAGAGAGAGGATCAGGAAAAATAGCTAATGGGTTCTAGGCTTAAC case32h/l-100 case32c/l-402 ACCTGAATGACAAAATAATGTGTACAGCAAACCCCCATGA ATTTACCTATCTAAC gnl|ti|529982443/82-484 ACCTGGGTGACAAAACAATGTGTACAGCAAAACCCCGTGACACAAATTTACCTATATAAA case32h/l-100 case32c/l-402 AAACCTGCACACGTACCCCTGGAACTTGAAAATTAAACTTTAAAAACCTGAAAATACAGA gnl | t i I 529982443/82-484 AAACTTGCACATGTACCCCTGGAATTTACAAGTTAAATTTTTAAAAACTGAGA GA case32h/l-100 case32c/l-402 ATGTCAAAAAA-TGATTTTCTATCTTTGTAAGTTTGGGATAATGGAAATCCACAGAGACA gnl|ti|529982443/82-484 ATGTCAAGAAAGTGATGTTCTATCTTTGTAAGTTTGGGATGATGGAAATCCACAGAGATA case32h/l-100 case32c/l-402 GAATAAATAAGGTTTCAAGATCCCCTACAATCCTTATAGAGAAGCTGAG gnl|ti|529982443/82-484 GAATAAATAAGGTTTCAAGATCCC-TACAATCCTTATAGAGAAGCTGAG case32h/l-100 -AATAAATAAGGTTTCAAGATCCCCTACAATCCTTATAGAGAAGCTGAG chrl2:48585272:48585595:scaffold_37077:4241894:-...precise d e l e t i o n of AluSx i n chimpanzee CLUSTAL case33h/l-48 6 TTAAGTGTGTTTGTGCAAAATTGGTGGTTATGGAGTGGGGGACAAAGGGCAAAAAGGGGT gn l | t i I 540393548/121-601 TTAAGTGTGTTTGTACAAATTTGGTGGTTATGGAGTGGGGGACAAAGGGCAAAAAAGGAT case33c/l-163 TTAAGTGTGCTTGTGCAAAATTGGTGGTTATGGAGTGGGGGACAAAGGGCAAAAAGGGGT case33h/l-486 GGGAT AAAGACTTTGATAATT AGGCC AGGCACGGTGGCTCACACCTGTAATCCCAGCACT gnl|ti|540393548/121-601 GGGATAAAGACTTTGATAATTAGGCCAGGCGTAGTAGTTCATGTCTGTAATCCCAGCCCT case33c/l-163 GGGATAAAGACTTTGATAATTT case33h/l-4 86 TTGGGAGGCTGAGGAGGGTGGATCACTTGAGGTCAGGAGTTGGAGACCAGCCTGGCCAA-158 gnl Iti|54039354 8/121-601 case33c/l-163 TTGGGAGGCTGAGGTGGGCGGATCACTTGAGGTCAGGAGTTGGAGACCAGCCTGGTCCAG case33h/l-4 8 6 CATGGTGAAACCCTGTCTCTACTAAAAATACAAAA-TTAGCCGGGCGTGGT gnl|ti|540393548/121-601 TGCATTTCACATGGTAAAACCCTGTCTCTACTAAAAATACAAAAATTAGCCGGGCGTGGT case33c/l-163 case33h/l-486 GGTGCGCGCCTGTAATCCCAGCTACTCAGGAGGCTGAGGCAGGAGAATCACTTGAACCCG gnl|ti|540393548/121-601 GGTGCATGCCTGTAATCCCAGCTACTCGGGAGGCTGAGGCAGGAGAATCACTTGAACCCA case33c/l-163 case33h/l-486 GAAGACAGAGGTTGCAGTGAGCCAAGATTGTGCCACTGCACTCCAGCCTGAGCAACAGAA g n l | t i I 540393548/121-601 GAAGACAGAGGTGGTAGTGAGCCGAGATTGTGCCGCTGCACTCCAGCCTGAGCAACAGAG case33c/l-163 case33h/l-4 8 6 CAAGATTTTCTCTGTAAAAAAAAAAAAAAAAAAAAAAAAAAAGACTTTGATAATTTGTCT gnl | t i I 540393548/121-601 CAAGACTCTGTCTC AAAAAAAAAAAAAAAGGCTT—ATAATTTGTCT case33c/l-163 GTCT case33h/l-48 6 GCCTACCTGGGCCCTGCTTTCTCAGGGACTTTAGGTGGGTCCCTGGGCAGTGAGAGGGAA g n l | t i I 540393548/121-601 GCCCACC-GGGCCCTGCTTTCTCAAAGTCTTTAGGTGGGTCCCTGGGCAGCGAGAGGGAA case33c/l-163 GCCTACCTGGGCCCTGCTTTCTCAGGGACTTTAGGTGGGTCCCTGGGCAGTGAGAGGGAA case33h/l-486 GCAGAAGGTAAGTGGCC gnl|ti|540393548/121-601 GCAGAAGGTAAGTGGCC case33c/l-163 GCAGAAGGTAAGTGGCC chr12:5530564 8:55305956:scaffold_36205:1170504 : + ...precise d e l e t i o n of AluY i n chimpanzee CLUSTAL case34h/l-4 64 AGGTTAAGGACCCCATTCATGAGGCAGGTTACAGAGTCCAACCTCAAAAGACTAAAAGTA gnl|ti|460701445/103-576 AGGTTAAGGACCCCATTCGCGAGGCAGGTTACAGAGTCCAACCTCAAAAGACTAAAAGTA case34c/l-156 AGGTTAAGGACCCCATTCATGAGGCAGGTTACAGAGTCCAACCTCAAAAGACTAAAAGTA case34h/l-4 64 GGAAGACCATCTATCTTTTAAAAACTTCT TGGCTCACGCCTGTAATC gnl|ti|460701445/103-576 GGAAGATGACCTATCTCTTAAAAACTTCTAGGCCAGGCGCGGTGGCTCAAGCCTGTAATC case34c/l-156 GGAAGACCATCTATCTCTTAAAAACTTCT case34h/l-4 64 CCAGCACTTTGGGAGGCCGAGACGGGCGGATCATGAGGTCAGGAGATCGAGACCATCCTG gnl|ti|460701445/103-576 CCAGCACTTTGGGAGGCCGAGACGGGCGGATCACGAGGTCAGGAGATCAAGACCATCCTG case34c/l-156 case34h/l-464 GCTAACACGGTGAAACCCCGTCTCTACTAAAAA—TACAAAAAT-TAGCCGGGCATGGTG gnl|ti|460701445/103-576 GCTAACCCGGTGAAACCCCATCTCTACTAAAAAAATACAAAAATCTAGCCGGGCGAGACG case34c/l-156 case34h/l-464 GCGCGCGCCTGTAGTCCCAGCTACACGGGAGGCTGAGGCAGGAGAATGGCGTGAACCCGG gnl|ti|460701445/103-576 GCGGGCTCCTGTAGTCCCAGCTACTTGGGAGGCTGAGGCAGGAGAATGGCGTGAACCCGG case34c/l-156 case34h/l-464 GAGGCGGAGCTTGCAGTGAGTCGAGATCGCGCCACTGCACTCCAGCCTGGGCGACACAGC g n l | t i I 460701445/103-576 GAGGCAGAGCTTGCAGTGAGCTGAGATCCGGCCACTGCACTCCAGCCTGGGCGACAGAGC case34c/l-156 case34h/l-4 64 GAAACTCCGTCTCAAAAAAAAAAAAAAAAAAAAAACAACAACAAAAAACTTCTTCCTTTC gnl | t i | 460701445/103-576 CAGACTCCGTCTCAGGAAAAAAAAAAAAAAAAAAAAAA AACACTTCTTCCTTTG case34c/l-156 TCCTTTC case34h/l-4 64 TTTGGTAAATTTTTGGCAAGATTACAGTATTTTAGTCTGCAAAATGCCCCCATAATAACT gnl|ti|460701445/103-576 TTTGGTAAATTTTTGGCAAGATTACAGTATTTTAGTCTGCAAAATGCCCCCATAATAATT case34c/l-156 TTTGGTAAATTTTTGGCAAGATTACAGTATTTTAGTCTGCAAAATGCCCCCATAATAACT chr12=122703868:122704186:scaffold_37680:2506194:-...precise d e l e t i o n of AluY i n chimpanzee 159 CLUSTAL case35h/l-479 CAACCTCTGGTCTAGACCAACCAATCCAATCATTACCTATCCCACTGGCTATAAACTATC gnl|ti|526305977/153-631 CAACCTCTGGTCTAGACCAACCAATCCAATCATTACCTATCCCACTGGCTATAAATTATC case35c/l-161 CAACCTCTGGTCTAGACCAACCAATCCAATCATTACCTATCCCACTGGCTATAAACTATC case35h/l-47 9 TGAAATTAAATAAGTGTGTCGG-TGTG TCGGTGGCTCACGCCTGTAATCCCA gnl|ti|526305977/153-631 TGAAATCAAATAAGTGTGTTTGCCATGGGCCGGGCACGGTGGCTCAAGCCTATAATCCCA case35c/l-161 TGAAATTAAATAAGTGTGTCTGCCATG case35h/l-479 GCACTTTGGGAGGCTGAGGCGGGCAGATCACGAGCTCAAGAGATCGAGACCATCCTGGCT gnl|ti|526305977/153-631 GCACTTTGGGAGGCCGAGATGGGCAGATCACGAGGTCAGGAGATCGAGACTATCCTGGCT case35c/l-161 case35h/l-47 9 AACACGGTGAAACCCCGCCTCTACTAAAAA-TACAAAAAATTAGCCGGTCGTGGTGGCGG gnl|ti|526305977/153-631 AACACGGTGAAACCCCGTCTCTACTAAAAAATACAAAAAACTAGCCGGGCGAGCTGGC--case35c/l-161 case35h/l-47 9 GCGCCTGTAGTCCCAGCTACTCGGGAGGCTGAGGCAGGAGAATGGCATGAACCTGGGAGG gnl|ti|526305977/153-631 CCATAGTCCCAGCTACGCGGGAGGCTGAGGCAGGAGAATGGCGTAAACCCGGGAGG case35c/l-161 case35h/l-479 CGGAGCTTGCAGTGAGCCGAGATTGCGCCACTGCACTCCAGCCTGGGTGACAGAGCGAGA gn l | t i I 526305977/153-631 TGGAGCTTGCAGTGAGCTGAGATCCAGCCACTGCACTCCAGCCTGGGCGACAGAGCGAGA case35c/l-161 case35h/l-479 CTCCGTCTCCAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAGTGTGTCTGCCATGTTTTC gnl | t i I 526305977/153-631 CTCCGTCTC AAAAAAAAAAAAAAAAAAAAAAAAAAAAGTGTGTCTGCCATGTTTTC case35c/l-161 TTTTC case35h/l-479 ACTTATTTTGTGCTCAGGGACATGGGCAGGTCAAGGACAAAGTCATCGCCTTCAACTACA gnl|ti|526305977/153-631 ACTTAATTTGTGCTCAGGGACATAGGCAGGTCAAGGACAAGGTCATCACCTTCGACTACA case35c/l-161 ACTTAATTTGTGCTCAGGGACATGGGCAGGTCAAGGACAAGGTCATCGCCTTCGACTACA case35h/l-479 AACATCCCT gnl|ti|526305977/153-631 AACATCCCT case35c/l-161 AACATCCCT chrl4:76323357:76323468:scaffold_37670:5922279:-...imprecise d e l e t i o n of L2 (element i n s i d e a deletion) i n chimpanzee, no f l a n k i n g i d e n t i t y CLUSTAL case36h/6-211 CCTGCCAGCATGGGAGAATGGCACTCCAAGGGGCACAGCCAGGGCGCTCCAGGGGGCAGG gnl|ti|538237539/116-325 CCTGCCAGCATGGGAGAACGGCACTCCAAGGGGCAGAGCCAGGGCACTCCAGGGGGCAGG case36c/6-100 CCTGCCAGCATGGGAGAATGGCACTCCAAGGGGCATAGCCAGGGC case3 6h/6-211 AACCCCAGGGGCTGGTGTAGTACCTGGCACAGAGGAGGTGCTCAATAAATGCACATGAGT gnl|ti|538237539/116-325 GACCCCAGGGGCTGGTACAGTACCTGGCACAGAGGAGGTGCTCAGTAAATGCACATGAGT case36c/6-100 case3 6h/6-211 AAATAAGAGGAGGATGGGGAGAAGTTGGATCAGTGCTGGAAAGAAG CAAACAATAT gnl|ti|538237539/116-325 AAACAAGAGGAGGATGGGGAGAAGTTGGATCAGCGCTGGAAAGAAGGCAGCAAAGAATAT case36c/6-100 TGGAAAGAAG CAAACAATAT case36h/6-211 GAGAGCCTGGAGGCATCTCTCCCCTGCGGG gn l | t i I 538237539/116-325 GAGAGCCTGGAGGCATCTCTCCCCTGTGGG case36c/6-100 GAGAGCCTGGAGGCATCTCTCCCCTGCGGG chrl4:81720447:81720771:scaffold_37670:482346:-...AluY with p a r t i a l d e l e t i o n i n Rhesus, gene conversion to AluYb8 i n human, preci s e d e l e t i o n i n chimpanzee CLUSTAL 160 case37h/l-488 CAGTGTATTTGAAAGAAAAAAATAAGTTTCCAAATTTTTCACAGCTTATCTTCTTTATGG gnl|ti|520934604/378-835 CAGTATATTTGAAAGAAAAAA-TAAGTTTCCAAATTTTTCCCATCTTATCTTCTTTACAG case37c/l-164 CAGTGTATTTGAAAGAAAAAAATAAGTTTCCAAATTTTTCCCAGCTTATCTTCTTTATGG case37h/l-488 CTCTTTAAAAGGTCACTTATGGGCCGGGCGCGATGGCTCACGCCTGTAATCCCAGCACTT gnl | t i | 520934604/378-835 CCCTTTAAAAGCTCACTTATG T case37c/l-164 CTCTTTAAAAGGTCACTTATG case37h/l-488 TGGGAGGCCGAGGCGGGTGGATCATGAGGTCAGGAGATCGAGACCATCCTGGCTAACAAG gnl | t i | 520934604/378-835 TGGGAGGCCGAGATGGGCAGATCACGAGGTCAGGAGATCGAGAGCATCCTGGCTAACACG case37c/l-164 case37h/l-488 GTGAAACCCCGTCTCTACTAAAAATACAAAAAAAATTAGCCGGGCGCGGTGGCGGGCGCC g n l I t i I 520934604/378-835 GTGAAACCCCATCTCTACTAAAAA-ATACAAAAAACTAGCCAGGCGAGGTGGTGGGCGCC case37c/l-164 — ' case37h/l-488 TGTAGTCCCAGCTACTCGGGAGGCTGAGGCGGGAGAATGGCGTGAACCCGGGAAGCGGAG gnl|ti|520934604/378-835 CGCAGTCCCAGCTACTCTGGAGGCTGAGGCAGGAGAATGGCGTGAACCCGGGAGGCAGAG case37c/l-164 case37h/l-488 CTTGCAGTGAGCCGAGATTGCGCCACTGCAGTCCGCAGTCCCGCCTGGGCGACAGAGCAA gnl | t i | 520934604/378-835 GTTGCAGTGAGTTGAGATTCGACCACTGCACTCCA GCCTGGGAGACAGAGCGA case37c/l-164 case37h/l-488 GACTCCGTCTCAAAAAAAAAAAAAAAAAAAAAA AGGTCACTGA gnl|ti|520934604/378-835 GACTCCGTCTCATAAAAAAAAAAAAAAAAAAAAGAAAAAAAAGAAAAAAAAGCTCACTTA case37c/l-164 case37h/l-488 TGAAAAAGTTTGAATTTCTAGAGCAGACACAGTTCATAGTCACTGAAGTTGTGACCTCTC g n l | t i I 520934604/378-835 TGAAAAACTTTGAATTTGTAGAGCAGGCACAGTTCATAGTCACTGAAGTTGTTGCCTCTC case37c/l-164 —AAAAAGTCTGAATTTCTAGAGCAGACACAGTTCATAGTCACTGAAGTTGTGACCTCTC case37h/l-488 TTGACAGAGAAGAAAGAGAGTAATA g n l | t i I 520934604/378-835 TTGAGAGAGAAGAAACAGAGTAATA case37c/l-164 TTGAGAGAGAAGAAAGAGAGTAATA chr15:37146781:37147081:scaffold_37412:10461989:-. . . p a r t i a l l y d e l e t e d AluJo e x i s t i n g p r i o r to human-rhesus s p l i t , no t s d ; imprecise d e l e t i o n i n chimpanzee, no TSDs or f l a n k i n g i d e n t i t i e s CLUSTAL case38h/l-400 TTAGCAATCATTTTGGAGGGAGTGTGCTAGACATTAAAAAAAA-TTATTAACACACATGG gnl|ti|523788521/312-713 TTGGCAATCATTTTAGAGGGAGGGTGCTAGACATTAAAAAAAAATTATTAACACACATGG case38c/l-131 TTAGCAATCATTTTGGAGGGAGTGTGCTAGACATTAAAAAAAA-TTATTAA case38h/l-400 TTCTGGCCAGGCATGGTGGTTCATGCATATAATCC-AGCACTTTGGGAGGCCAAGGTGGA gnl|ti|523788521/312-713 TTCTGGCCAGGCATGGTGGTTCATGCATATAATCCCAGCACTTTGGGAGGCCAAGGTGGA case38c/l-131 case38h/l-400 AAGATCCCTTGAGTCTCAGAATTTGAGACCAGCCTTGGCAACATAGTGAGGCCCCCATCT gnl|ti|523788521/312-713 AAGATCCCTTGAGTCTCAGAATTTGGGACCAGCCTTGGCAACATAGTGAGACCACCATCT case38c/l-131 case38h/l-400 CTACAGAAAATAAAAAAAAATTAGCTGGGCATGATGACACACACCTGTAGTCCCAGTTAC gnl|ti|523788521/312-713 CTACAGAAAATAAAAAAA--TTAGCTGGGCGTGATGCTACACACCTGTAGTCCCAGTTAC case38c/l-131 case38h/l-400 TTGGGAAGCTGAGGTGGGAAGGACTGCTTGAGCACAGGAGTTTGAGGCTGCAGTGAGCCA gnl|ti|523788521/312-713 TCAGGAAGCTAAGGTGG-AAGGACTGCTTAAGCACAGGAGTTTGAGGCTGCAGTGAGCCG case38c/l-131 case38h/l-400 CGATTGCACTACTGCACTTCAGCCTGGGCAACAGAGTGAGACCTTGTCTTAAAAGTAAAT gnl|ti|523788521/312-713 TGACTGCACTACTGCACTTCAGCCTGCGCAACAGAGTGAGACCTCGTCTTAAAAATAAAT case38c/l-131 ATAAGTTAAATTATTAAATTATTAAATTATTAAATAAAT case38h/l-400 AA GTAAAGACACGTGGTCCTTCAAAGAGAGAGGTATAAACAA 161 gnl|ti|523788521/312-713 AAATAAAGTAAAGACACATGGTCCTTCAAAGAGAGGTG--TAAACAA case38c/l-131 AA GTAAAGACACGTGGTCCTTCAAAGAGAGAGGTATAAACAA chr15:50365066:scaffold_37399:651713:652024:-...precise d e l e t i o n of AluSq i n human CLUSTAL case39c/l-457 TAACACTTAACACTACTCTGAATTCATGAAAGACCAAAGGTAGCTAATTAATATACAATT gnl|ti|459269000/431-893 TAACACTTAACACTACTGTGAATTCACAAAAGACCAAAGGTAGCTAATGAATATACAATT case39h/1-150 TAACACTTAACACTACTCTGAATTCATGAAAGACCAAAGGTAGCTAATTAATATACAATT case39c/l-457 CCTGAAAATAAAAATTATTCAATCTCATCAAAAGTCAAAGAAGGCCAGGCGCAGTGGCTC gnl|ti|459269000/431-893 CCTGAAAATAAAAATTATTCCGTCTCTTCAAAAGTCAAAGAAGGCCAGGCGCAGTGGCTC case39h/l-150 CCTGAAAATAAAAAAAA AAAAAAAAAAGTCAAAGAA case39c/l-457 ATGCCTGTAATCCCAGCACTTTGGGAGGGCAAGGCAAGTGGGTCACCTGAGGTCAGGAGT gnl|ti|459269000/431-893 CTGCCTGTAATCCCAGCACTTTGGGAGACCCAGGCCAGTGGATCACCTGAGGTCAGGAGT case39h/l-150 case39c/l-457 TCGAGAGCAGCCTAGCCAACATCGTGAAACCCCGTCTCTACTAAAAATACAAAAAATTAG gnl|ti|459269000/431-893 TCGAGACGAGCCTAGCCAACATGGCGAAACCCTGTCTCTACTAAAAATACAAAAAATTAA case39h/l-150 case3 9c/l-457 CCAAGTGTGGTGGCAGACACCTGTAATCCCAGCTACTCAGGAGGTTGAGGCAGGAGAATT gnl|ti|459269000/431-893 CCAAGTGTGGTGGCAGGCGCCTGTAATCCCAGCTACTCAGGAGACTGAGGCAGGAGAATT case39h/l-150 case39c/l-457 GCTTGAACCCAGGAGGCAGAGGTTGCAGTGAGCTGAGATTGTGCCATTGCACTCCAGCCT gnl|ti|459269000/431-893 GCTTGAACCCAGGAGGTGGAGGTTGCAGTGAGCCGAGATTGCACCACGGCATGCCAGCCT case39h/l-150 case39c/l-457 AGGCAACAAGAGCAAAACTCGGTCCAA AAAAAAAGTCAAAGAAATGCAAATTAA gnl | t i | 459269000/431-893 GGGCAACAAGAGCAAAACTCCGTCCAAGAAAAAAAAAAAAGTCAAAGAAATGCAAATTAA case39h/l-150 ATGCAAATTAA case39c/l-457 ATCAACAGCAAAGTGCCACTTTTGGTCTATTAACTGAGCTAAT gnl|ti|459269000/431-893 ATCAACAACAAAGTTCCACTTTTGGTCTATTAACTGAGCTAAA case39h/l-150 ATCAACAGCGAAGTGCCACTTTTGGTCTATTAACTGAGCTAAT chrl6:48429275:scaffold_32947:3554158:3554416:+ ...precise d e l e t i o n of AluY i n human CLUSTAL case40c/16-44 9 AAAATATATATATATATATATGTTTATATAGAATATCTTCCATGCCACAGCAATTCCATC gnl|ti|536342151/145-590 TATATATATATATATATATATATATATAAAAAATATCTTCCATACCACAGCAATTCCATC case40h/16-150 TATATATATATT-ATATATATATATA TTCCATC case40c/16-449 CAATCACCTTTCTCAAACATGAAGGGGGGTGGAACACGAGGT-CAGGAGATCAAGATCAT gnl I t i | 536342151/145-590 CAATCCCCTTTCTCAAACATGAAGGGGGGCAGATCACCAGGTTCAGGAGATCAAGACCAT case40h/i6-150 CAATCCCCTTTCTCAAACATGAAGGGG case40c/16-449 CCTGGCTAACACGGTGAAACCCCATCTTTACTAAAAATACAAAAACAAAATTAGCCGGGC gnl|ti|536342151/145-590 CCTGGCTAACATGGTGAAACCCTGTCTCTACTAAAAAGACAAAAACAAAATTAGCCGGGT case40h/16-150 case40c/16-4 4 9 GTGGTGGCAGGCGCCTATAGTCCCAGCTACCAGGGAGGCTGAGG-CAGGAGAATGGCGTG gnl|ti|536342151/145-590 GTGGTGGCAGGTGCTTGTAGTCCCAGCTACTCAGGAGGCTGAGG-CAGGAGAATGGTGTG case40h/16-150 case40c/16-44 9 AACCCAAGAGGCGGAGCTTGCAGTGAGCCGAGATCGCACCAGTGCACTCCAGCCTAGGTG gnl|ti|536342151/145-590 AACCCAGGAGACGGAGCTTGCAGTGAGCAGAGATCGCGCCACTGCACTCCAGCCTACGTG case40h/16-150 162 case40c/16-449 ACAGAGCGAGACTCCGTCTCAAAAAAAAAAAAAA AACCATGAAGGGGCTG gnl | t i | 536342151/145-590 ACAGAGCGAGACTCCATCTCAAAAACAAAAACAAAAACAAAACAAAACATGAAGGGGCTA case40h/16-150 CTG case40c/16-44 9 GGCTTC-TCTCGGCATGGTAGCCAGGTTCCAAGTAAGAAAGTAAGACTATTTCACCAGCA gnl|ti|536342151/145-590 GGCTTCCTCTCAGCATGGNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNN case40h/16-150 GGTTTCCTCTTGGCATGGTAGCCAGGTTCCAAGTAA GACTATTTCACCAGCA case40c/16-449 AGTGTTCTTGCTGGAAGTAGAAGGAAG gnl|ti|536342151/145-590 NNNNNNNNNNNNNNNNNNNNNNNNNNN case40h/16-150 AGTGTTCC ATGAAAAAGGAAG chr16:6657598 4:6657 6310:scaffold_37667:3291777:-...AluY i n Rhesus, gene conversion to AluYb8 i n human, p r e c i s e d e l e t i o n i n chimpanzee CLUSTAL case41h/l-4 91 CTCTTCACTTCCATTCTATTCATTAACTCCTTTTGTTCCACCTTGAACTATGCTCATTTT gnl|ti|536041529/83-557 CTCTTTACTCCCATTCTATTCATTAACTCCTTTTGTTCCACCTTAAACTATGCTCGTTTC case 41c/1-165 CTCTTCACTTCCATTCTATTCATTAACTCCTTTTGTTTCACCTTGAACTATGCTCATTTT case41h/l-4 91 TCCTCATCTTAAAAAAATACCC GGCCGGGCGCGGTGGCTCACGCCTGTAATCCCA gnl|ti|536041529/83-557 TCCTCATCTCAAAAAAATACCCAATAGAGCCGGGCGCAGTGGCTCACGCCTGTAATCCCA case41c/l-165 TCCTCATCTTAAAAAAATACCCAATAG case41h/l-491 GCACTTTGGGAGGCCGAGGCGGGTGGATCATGAGGTCAGGAGATCGAGACCATCCTGGCT g n l | t i I 536041529/83-557 GCACTTTGGGAGGCCAAGGCGGGCGGATCACAAGGTCAGGAGATCGAGACCAC case41c/l-165 case41h/l-4 91 AACAAGGTGAAACCCCGTCTCTACTAAAAA-TACAAAAAATTAGCCGGGCGCGGTGGCGG gnl|ti|536041529/83-557 GGTGAAACCCCGTCTCTACTAAAAAATACAAAAAATTAGCCGGGTGCTGTAGCGG case41c/l-165 case 4 lh/1-4 91 GCGCCTGTAGTCCCAGCTACTCGGGAGGCTGAGGCAGGAGAATGGCGTGAACCCGGGAAG gnl|ti|536041529/83-557 GCGCCTGTAGTCCCAG GAGGCTGATGTTTGAGAATGGCGTGAACCTGGGAGG case41c/l-165 case41h/l-491 CGGAGCTTGCAGTGAGCCGAGATTGCGCCACTGCAGTCCGCAGTCCGGCCTGGGCGACAG gnl | t i I 536041529/83-557 CGGAGCTTGCAGTGAGCCAAGATCGCGCCACTGCACTCCA GCCTGGGGGACAG case41c/l-165 . case41h/l-491 AGCGAGACTCCGTC T C AAAAAAA AAAAAAAAAAAAAAAAAAAAAAAAAATACCCA gnl|ti|536041529/83-557 AGCGAGACTCCGTCTCAACAACAACAACAACAACAAAACAAAACAAAACAAAAACACCCA case41c/l-165 case41h/l-491 ATAGTTTGTTTGATTTGCTATCCTTTCAATTATTCATCCACTCCTCCCAGCAGATGCACA gnl | t i | 536041529/83-557 ATAGTTTGTTTGATTTGCTATCCTTTCAAGTATTCATTCACTCCTCCCAACAGATGCAAG case41c/l-165 TTTGTTTGATTTGCTATCCTTTCAATTATTCATCCACTCCTCCCAGCAGATGCACA case41h/l-4 91 TATACCATTAGAAAGTAAATGT gnl|ti|536041529/83-557 TATCCCATTAGATAGTAAATGT case41c/l-165 TATACCATTAGAAAGTAAATGT chrl6:69279114:69279432:scaffold_37667:485635:-... p r e c i s e d e l e t i o n of AluSq i n chimpanzee CLUSTAL case42h/l-47 9 TTCTGAAACCCACGTCTCTTGACAACTATGGTCTCTGCAACTTATCTGACCTTAAAACAC gnl|ti|536066149/241-714 TTCTGAAACCCACATATCTTGACAACTATGGTCTCTGCAACTTATCTGACCGTAAAACAC case42c/l-161 TTCTGAAACCCACGTCTCTTGACAACTATGGTCTCTGCAACTTATCTGACCTTAAAACAC case42h/l-479 TTGCCTGGGTAATGTCCTTATAAGAGTTCTTCCTTTCTGGCCGGGCGCGGTGGCTTACAC gnl|ti|536066149/241-714 TTGCCTGGGTAATGTCCTTGTAAGAGTTCTTCCTTTCTGGCCGGATGCGGTGGCTCACGC 163 case42c/l-161 TTGCCTGGGTAATGTCCTTATAAGAGTTCTTCCTTTC case42h/l-479 CTGGAATCCCAGCACTTTGGGAGGCCGAGGTGGGTGGATCACTTGAGGTCAGGAGTTT-G g n l | t i I 536066149/241-714 CTGTAATCCCAGCACTTTGGGAGGCCGAGGCGGGTGGATCACTTGAGGTCAGGAGTTTTG case42c/l-161 case42h/l-47 9 . ATACCAGCCTGGCCAACGTGGTGAAACCCTGCCTCTACTAAAAATACAAAAATTAGCTGG gnl | t i I 536066149/241-714 AGACCAGCCTGGCCAACATGGTGAAACCCTGTTTCTATTAAAAATACAAAAGTTATCTGG case42c/l-161 case42h/l-479 ACCTGGTAGTGCATGCCTGTAATCCCAGCTACTTGGGAGGCTGAGGCAGGAGAATCTCTT g n l I t i I 536066149/241-714 ACGTGGTAGTGCATGCCTGTAATCCCAGCTACTCGGGAGGCTGAGGCAGGAGACTCTCTT case42c/l-161 case42h/l-479 GAACCTGGGAGGTGGAGGTTGCAGTGAGCTGAGATCGCACCATTGCATTCCGGCCTGGGG g n l | t i I 536066149/241-714 GAACCTGGGAGATGGGGATTGCAGTGAACTGAGATCGTGCCACTGCACTCCAGCCTGGGG case42c/l-161 case42h/l-47 9 GACAAGAGTGAAACTCCATCTCAAAAAAAAAAAAAAAAAAAAGAGTTCTTCCTTTCCAAG gnl|ti|536066149/241-714 GACAAGAGTGAAACTCCATCTCAGGGAAAAAA AAAAGTTCTTCCTTTCCAAG case42c/l-161 CAAG case42h/l-479 TATACCTGAGTTCCCATAAGACAGAAAGTCATTTTGTTG-CTGTTAATTTTTTGAG-TAA g n l | t i I 536066149/241-714 TATACCTAAGTTCCCATAAGACAGAAAGTCACTTTTTTGGTTGTTAATTTTTTGAGATAA case42c/l-161 TATACCTGAGTTCCCATAAGACAGAAAGTCATTTTGTTG-TTGTTAATTTTTTGAG-TAA case42h/l-479 GG g n l | t i I 536066149/241-714 GG case42c/l-161 GG chrl6:74232245 = 74232552:scaffold_37614:14060425:-. . .precise d e l e t i o n of AluSx i n chimpanzee, 3 copies of t h i s region i n human genome, a l l with the A l u , chimpanzee has one with the A l u , one without CLUSTAL case43h/l-4 62 CAGCCACACCTCTCTGCCCTAGTCTCCTGCCCCCAGGAGCCTGGCCTCATATGCTCCCCA gnl|ti|503026621/313-769 CAGCCACGCCTCTCCGCCCTGGTCTCCTGTCCCCGTA CCCGCCTCATCGGCTCCCTA case4 3c/1-155 CAGCCACGCCTCTCTGCCCTAGTCTCCTGCCCCCAGGAGCCTGGCCTCATATGCTCCCCA case43h/l-4 62 CCACGCACAGCTGACCCCGCCCCCTCCCTCTTCTTTTTTTTTTTTGAGACAGAGTCTCAC gnl|ti|503026621/313-769 CCACGCACAGCTAACCCCGCCCCCTCCCTCTTCTTCTTTTTTTT-AAGACAGAGTCTCAC case43c/l-155 CCACGCACAGCTGACCCCGCCCCCTCCCTCTTCTT case43h/l-4 62 CCTGTCGCCCAGGCTGGAGTGCAGTGGAGAAATCCC—GGCTTACTGCAACCTCCGCCTC gnl|ti|503026621/313-769 CCTGTTGCCCAGTCTGGAGTGCAGTGGAGCAATCTC—GGCTTACTGCAAACTCCGCCTC case43c/l-155 case43h/l-4 62 CCAGGTTCAAGCAATTCTCCTGCCTCAGCCTCCCAAGCAGCTGGGATTACAGCCATGTGA g n l | t i I 503026621/313-769 CCAGGTTCAAGCGATTCTCCTGCCTCAGCCTCCCGAGTAGCTGGGATTAGAGCCATGTGA case43c/l-155 case43h/l-462 CACCACACCTGGCTAATTTTTGTATTTTTAGTAGAGACGGGGTTTCACCATGTTGGCCAT gnl|ti|503026621/313-769 CACCACATCTGGCTAATTTTTGTATTTTTAGTAGAGACAGGGTTTCACCACGTTGGCCAT case43c/l-155 case43h/l-462 TGCTGGTGTCAAACTGCTGACCTTAGGTGATCTGCTTGTGTCAGCCTCCCAGAGTGCTGG g n l | t i I 503026621/313-769 -GCTGGTCTCAAACTGCTGACCTTAGGTGATCTCCTTGCGTCAGCCTCCCAAAGTGCTGG case43c/l-155 case43h/l-4 62 GATTACAGGTGTGAGCCACCGTGCCCAGCCCCCTCCCTCTTCTTAAACAAGGGGCCTGGC gnl|ti|503026621/313-769 GATTACAGGTGTCAGCCACCGCGCCCAGCCCCCTCCCTCTTCTTAAACAAGGGGCCTGGC case43c/l-155 AAACAAGGGGCCTGGC case43h/l-4 62 AATCACCACCCCTGGGTGACTTGGTGCAGTCCCCTGATCTCCCG g n l | t i I 503026621/313-769 AATCGCCACCCCTGGGTGACCTGCTGCAGACCCCTGATCTCCCG case43c/l-155 AATCACCACCCCTGGGTGACTTGGTGCAGTCCCCTGATCTCCCG 164 chr17:30401123:30401435:scaffold_37172:1193530:+ ...imprecise d e l e t i o n of AluSc i n chimpanzee (no TSD copy retained) CLDSTAL case44h/l-470 ACCCATTAGAAGATAACACCATTTGCCTTTTATTTTTGGATAATTCAGGAATAAAAAATG g n l | t i I 513289005/92-572 ACCCATTAGAAGATAACAGCACTTGTCTTTTGTTTTTGGATAATTCAGGAATAAAAAATG case44c/l-161 TCCCCCTATAAGATAACACCATTTGCCTTTTATTTTTGGATCATTCAGGAATAAAAA-TG case44h/l-470 GATCTCAAGCTTTATAAAACTTACAATTCTAGGCTGGGCGCTGTGGCTCACACCTGTAAT g n l | t i I 513289005/92-572 GAACCCAAGTTTTATAAAACTTACAATTCTAGGCTGGGCGCCATGGCACACGCATGTAAT case44c/l-161 GATCTCAAGCTTTATAAAACCC case44h/l-470 CCCAGCACTTTGGGAGGCCAAGGCCGGCGGATCACACGGTCAGGAGGTCAAGACCATCCT g n l | t i I 513289005/92-572 CTCAGCACTCTGGGAGGCCAACGCAGGTGGATCACACAGTCAGGAGGTCAAGACCATCCT case44c/l-161 case44h/l-470 GGCCAACATGGTGAAACCCTGTCTCTACTAAAAATACAAAAATTAGCTGGGCGTGGTGGT gnl | t i I 513289005/92-572 GGCCAACATGGTAAAACCCTGTCTCTACTAAAAATACAAAAATTAGCTGGGCGTGGTGGT case44c/l-161 case44h/l-470 GCGAGCCTGTAATCCCAGCTACTCGAGAGGCTGAGACAGGAGAATTGCTTGAACCCAGGA g n l I t i I 513289005/92-572 GCGAGCCTGTAATCCCAGCTACTCCGGAGGCTGAGACAGGAGAATTGCTGGAACCCGGGA case44c/l-161 case44h/l-470 GGCAGAGATTGCAGTGAGCCGAGATTGTGC-CACTGCACTTCAGCCTGGCAACAGAGTGA gnl|ti|513289005/92-572 GGCAGAGATTACAGTGAGCTAAGATTGTGT-CGCTGCACTCCAGCCTGGCAACCCAGCAA case44c/l-161 case44h/l-470 AACTCCGTCTCAAAAA AAAAAAATTATAATTCTATAGAAAAATAACATTTGTAT gnl | t i | 513289005/92-572 AACTCCATCTCAAAAAAAAAGAAAAAAAATTATAATTCTATAGAAAAAGAACATTGGTAT case44c/l-161 CATAGAAAAATAACATTTGTAT case44h/l-470 AAATTTAAC-TTTGGTGTA AAAAAGTGAATTTAACTTTGGTATTGCACACTGGTA gnl | t i | 513289005/92-572 AAATTTAAC-TTTAGTGTAGAAGAAAAAAGTGAATTTAACTTTGGTATTGCACACTGGAA case44c/l-161 AAATTTAACCTTTGGTGTA AAAAAGTGAATTTAACTTTGGTATTGCACACTGGTA case44h/l-470 ATT gnl|ti|513289005/92-572 AGT case44c/l-161 ATT chrl7:37731003:scaffold_37479:3983548:3983669:-...imprecise d e l e t i o n i n t e r n a l to MIRb element i n human, no f l a n k i n g i d e n t i t y CLUSTAL case45c/1-221 CAGAATCGATCACTAAAAGATGTTAGTGTTTTTACGCCACTGCGGGTCTTTAATTTCTTG g n l | t i I 529975753/582-804 CAGAATAGATCACTAAAAGATGTTAGTGTTTTTACGCTGCTGCGGGTCTTTAATTTCTTG case45h/l-100 CAGAATCGATCACTAAAAGATGTTAGTGTTTTTACGCCACTGCGGGTCTT case45c/l-221 GTGCCTCAATTTCCTCCTCTGTAAAGTGGACCTAATCCCAATATTTCTGTCATCAGTTGT gnl|ti|529975753/582-804 GTGCCTCAATTTCCTCCTCTGTAAAGTGGACCTAATCCCAATGTTTCTATCATCAGTTGT case45h/l-100 case45c/l-221 GGAAATTACGTGAGGTAACGTTTGCAATTAGCAAAGGAAGGCATTAAGACAGCAAGCTCT gnl|ti|529975753/582-804 GGAAATTACGTGAGGTAACATTTGCAATTAGCAAAGGAAGGCATTAAGACAGCAAGCTCT case45h/l-100 GCAAGCTCT case45c/l-221 TGGAAGGCGGGAACTAGTCTC—AGTCTCATTTGGCTCACAAC gnl|ti|529975753/582-804 TGGAGGGCGAGAACTAGTCTCGTAGTCTCCTTTGGCTCACAGC case45h/l-100 TGGAGGGCGGGAACTAGTCTC—AGTCTCATTTGGCTCACAAC chrl7:57592534:57592845:scaffold 37 659:174722 63:+ 165 .AluY i n Rhesus, gene conversion to AluYb8 i n human, p r e c i s e d e l e t i o n i n chimpanzee CLUSTAL case46h/l-468 AGAAAGAATATAGAGCTTAGGTTGGAGTTGAAATGGTGAGGACTAGTATTTAAGAAATCT g n l I t i I 541136674/627-1103 AGAAAGAATATAGGGCTTAGGTTGGAGTTGAAATGGTGAGGACTAGTATTTA-GAAGTCT case46c/l-157 AGAAAGAATATAGAGCTTAGGTTGGAGTTGAAATGGTGAGGACTAGTATTTAAGAAATCT case4 6h/l-4 68 TTAGTTATCCCAGCATATTAAGAATATGCCA GGCCGGGCGCGGTGGCTCACGCCT g n l | t i I 541136674/627-1103 TTAGTTATCCAAGCATATTAAGAGTATGCCAGTGTTGGCCAGGCGCAGTGGCTCACGCCT case46c/l-157 TTAGTTATCCAAGCATATTAAGAATATGCCAGTGTT case46h/l-468 GTAATCCCAGCACTTTGGGAGGCCGAGGCGGGTGGATCATGAGGTCAGGAGATCAAGACC g n l | t i I 541136674/627-1103 GTAATCCCAGCACTTTGGGAGGCCAAGGCAGGCGGATCATGAGGTCAGGAGATCGAGACC case46c/l-157 1 case4 6h/l-4 68 ATCCTGGCTAACAAGGTGAAACCCCGTCTCTACTAAAAATACAAAAAATTAGCCGGGCGC gnl|ti|541136674/627-1103 ATCCTGGCTAACACAGTGAAACCCCGTCTTCACCAAAAATACAAAAAGTTCTCCGGGCGT case46c/l-157 case4 6h/l-4 68 GGTGGCGGGCGCCTGTAGTCCCAGCTACTCGGGAGGCTGAGGCAGGAGAATGGCGTGAAC gnl|ti|541136674/627-1103 GGTGGCGGGTGCCTGTAGTCCTAGCTACTCCGGAGGCTGAGGCAGGAGAACGGCGTGAGC case46c/l-157 -case46h/1-468 CCGGGAAGCGGAGCTTGCAGTGAGCCGAGATTGCGCCACTGCAGTCCGCAGTCCGACCTG g n l | t i I 541136674/627-1103 CTGGGAGGCGGAGCTTGCAGTGAGCCGAGATCACACCACTGTACTCCA-- GCCTG case46c/l-157 case46h/l-468 GGCGACAGAGCGAGACTCCGTCTCAAAAAAAAAAAAA GAATATGCCAG g n l | t i I 541136674/627-1103 GGCAACAGAGCGAGACTCCGTCTCAAAAAAAAAAAAAAAAAAAAAAGAAGAATATGCCAG case46c/l-157 case4 6h/l-4 68 TGTTCATACTGAGGAGAACATGGGTAAAACAGAAACAGTAGAAAGCTAACTTTTAATTAC g n l | t i I 541136674/627-1103 TGTTCACACTGAGGAGAACATGGGTAAAACAGAAACAGTAGAAAGCTAACTTTTAATTAC case46c/l-157 CATACTGAGGAGAACATGGGTAAAACAGAAACAGTAGAAAGCTAACTTTTAATTAC case46h/l-468 TCTAA gnl|ti|541136674/627-1103 TCTAG case46c/l-157 TCTAG Chrl7:79427256:79427568:scaffold_34699:232 697:+ ... AluY i n Rhesus has polymorphisms at head and t a i l , gene conversion to AluYg6 i n human, p r e c i s e d e l e t i o n i n chimpanzee CLUSTAL case47h/l-412 GAACGTCTTCCCATGTCATTAAACACAACAAAATAAGGTTAGGATAGATTAA-GATTGAA gnl|ti|503733953/300-735 GAACATCTTCCTATGTCATTAAACACAACAAAATAAGGTTAGGATGGATTAAAGATTGAA case47c/l-101 GAACGTCTTCCCATGTCATTAAACACAACAAAATAAGGTTAGGATAGATTAAAGATTGAA case 4 7h/1-412 CGTTTA GGCCGGGCGCGGTGGCTCACGCCTGTAATCCCAGCACT gnl | t i | 503733953/300-735 CATTTAAAATAAACCAT-AAGGGGCCAGGCGCGGTGGCTCACGCCTGTAATCACAGCACT case47c/l-101 CTTTTAAAACAAACCGTTAAG case47h/l-412 TTGGGAGGCCGAGACGGGCGGATCACGAGGTCAGGAGATCGAGACCATCCTGGCTAACAC gnl | t i I 503733953/300-735 TTGGGAGGCCGAGGCGGGCGGATCACGAGGTCAGGAAATCAAGACCATCCTGGCTAACAC case47c/l-101 . case47h/l-412 GGTGAAACCCCGTCTCTACTAAAAATACAAAAA-TTAGCCGGGCATGGTGGCGTGCGCCT gnl|ti|503733953/300-735 GGTGAAACCCCTTCTCTACTAAAAATACAAAAAATTAGCTGGGCGTGGTGGCGGGCACCT case47c/l-101 case47h/l-412 GTAGTCCCAGCTACTCGGGAGGCTGAGGCAGGAGAATGGCGTGAACCCGGGAGGCGGAGC gnl I t i I 503733953/300-735 GTAGTCCCAGCTACTTGGGAGGCTGAGGCAGGAGAATGGGGTGAACCCGGGAAGAGGAGC case47c/l-101 case47h/l-412 TTGCAGTGAGTCGAGATCGCGCCACTGCACTCCAGCCTGGGCGACAGAGCGAAACTCCGT gnl | t i | 503733953/300-735 TTGCAGTGAGCTGAGATCCGGCCACTGCACTCCAGCCTGGGCGACAGAGCGAGACTCCAT case47c/l-101 166 case47h/l-412 CTCAAAAAAAAAAAAAAAAA AAAGATTGAACGTTTA gnl|ti|503733953/300-735 CTCAAAAATAATAATAATAATAATAATAATAATATAATAAAATA case47c/l-101 case47h/l-412 AAACAAACCGTAAGACACCATGAAAGACCTGGTG gnl|ti|503733953/300-735 -AATAAACCATAAGACACCATGAAAGACCTGGTG case47c/l-101 ACACCATGAAAGACCTGGTG chr19:8420410:8420717:scaffold_37480:196649:-...AluY i n rhesus, gene conversion to AluYa5 i n human, pr e c i s e d e l e t i o n i n chimpanzee CLUSTAL case4 8h/l-4 62 GTCACCATGTCGTCACTAGGCCTCGGTCCTATGGAGGCTACTACCTACACGCTTACAGCT gnl|ti|496120749/118-591 GTCACCCTGTTGTCACTAGGCCTCGGTCCTATGGAGGTTACCACCTACACGCTAACAGCT case48c/l-155 GTCACCATGTCGTCACTAGGCCTCGGTCCTATGGAGGCTACTACCTACACGCTTACAGCT case48h/l-4 62 TTAAAAGAGACTCTTAGGCCGGGCGCGGTGGCTCACGCCTGTAATCCCAGCACTTTGGGA gnl|ti|496120749/118-591 TTAAAAGAGACTCTT-GGCCGGGCACGGTGGCTCAAGCCTGTAATCTCAGCACTTTGGGA case48c/l-155 TTAAAAGAGACTCTTA case48h/l-4 62 GGCCGAGGCGGGCGGATCACGAGGTCAGGAGATCGAGACCATCCCGGCTAAAACGGTGAA gnl|ti|496120749/118-591 GGCCGAAACGGGCGGATCACGAGGTCAGGAGATCGAGACCATCCTGGCTGACACGGTGAA case48c/l-155 case48h/l-4 62 ACCCCGTCTCTACT AAAAATACAAAAAATTAGCCGGGCGTAGTGGCGGGCGCCTGT gnl|ti|496120749/118-591 ACCCCGTCTCTACTTAAAAAAAATACAAAAAACTAGCCGGGCGAGGTGGCAGGCGCCTGT case48c/l-155 case48h/l-4 62 AGTCCCAGCTACTTGGGAGGCTGAGGCAGGAGAATGGCGTGAACCCGGGAGGCGGAGCTT g n l | t i I 496120749/118-591 AGTCCCAGCTACTCGGGAGGCTGAAGCAGGAGAATGGCGTGAACCCGGGAGGCGGAGCTT case48c/l-155 case48h/l-462 GCAGCGAGCCGAGATCCCGCCACTGCACTCCAGCCTGGGCGACAGAGCGAGACTCCGTCT gnl|ti|496120749/118-591 GCAGTGAGCTGAGATCCGGCCACTGCACTCCAGCCTGGGCAGCAGGGCGAGACTCCGTCT case48c/l-155 case48h/l-462 C AAAAAAAAAAAA AAAAGAGACTCTTAGCACACAGT GAGGC AATGATGT AT gnl | t i I 496120749/118-591 CAAAAAAAAAAAAAAAAAAAAAGAGACTCTTGGCACACAGTAACTGAGGCAATGATGTAT case48c/l-155 GC ACAC AGT GAGGC AATGATGTAT case48h/1-4 62 TTTTCTACCAATAATTTTATTGAGAAGGGTAGAGAGGGGGACTGATTCACTCCTA gnl|ti|496120749/118-591 TTTTCTACCAATAATTTTATCGAGAAGGGTAGAGAGGCGGACTGATTTACTCCTA case48c/l-155 TTTTCTACCAATAATTTTATTGAGAAGGGTAGAGAGGGGGGCTGATTCACTCCTA >chr19:41499856:41500219:scaffold_37497:2669080:-....rhesus has p a r t i a l tandem d u p l i c a t i o n of AluSq; chimp 3 d e l e t i o n s , i n c l u d i n g o r i g AluSq CLUSTAL case49h/l-4 63 AACATTTTTGGTAATTATTTT CTATATATTTTAGATATTTCATTAAACTAATAC gnl|ti|563501071/127-787 AACAGTTTTGGTAATTATTTTTACTTTCTATATATTTTAGAGTTTCCATTAAACTAATAT case49c/l-115 AACATTTTTGGTGATTATTTT CTGTGTATTTTAGGATTTCCATTAAACTA case4 9h/l-4 63 AGAATTTCATATTCAGGGCCAGGCATAGTGGCTCATGCCTGTAATCCCAGCACTTTGAGA gnl I t i I 563501071/127-787 AGAATTTCATATTCAGGGCCTGGTGCAGAGGCTCATACCTGTAATCC-AGCACTTTGGGA case49c/l-115 TATTC case49h/l-463 GTCCAAGGCGGGCGCATCACCTGAGGTCAGGGGTTCGAGACCATCCTGGCCAACAAGGGA gnl|ti|563501071/127-787 AGCCGAGATGGGCGGATCACCTGAGGTCAAGGGTTCGAGACCAGCCTGGCCAACATGGCC case49c/l-115 167 case4 9h/l-4 63 AAACCCCATCTCTATTAAAAATACAAAATTAGCCGGGTGTGGTGTTGCACGCCTGTAATC gnl|ti1563501071/127-787 ACACCCCGTCTCTACTAAAAATTCAAAATTAGTCGGGTGTGGTGGTGCATGCCTGTAATC case49c/l-115 case49h/l-4 63 CCAGCTACTTGGAAGGCTGAGGCAGGAGAATC g n l | t i I 563501071/127-787 CCAGCTACTTGGTATGCTGAGGCAGGAGAATCCATTGAAACTGCGAGGCGGAGTTTGCAG case49c/l-115 case49h/l-463 gnl|ti|563501071/127-787 TGAGCCAACATCACGCCATTGTACTCTAGCCTGGGCAACAGTAGTGAAACTCCAGCTCAA case49c/l-115 case49h/l-463 GCATG gnl | t i I 563501071/127-787 AAAAAAAAAAAAAAAAAAAAAAAAAATACAAAACTTAGCTGGGCATGTTGGCGGGTGCTG case49c/l-115 case49h/l-463 ACCCCGGGGGCAGAGA gnl|ti|563501071/127-787 ATAATCCCAGTCACTCGGTAGGCTGAGGCAGGAGAATTGCTTCAACCCAGGGAGCAGAGG case49c/l-115 case4 9h/l-4 63 TTGCAGTGAGCTGAGATCTTGCCACTTCATTCCAGCCTGGGCCACAGAGCAAGACTCCTT gnl I t i I 563501071/127-787 TTGCAATGAGCCAAGATCTCATGACTTCGCTCCAGCCTGGGGCACAGGGCAAAACTCCTT case49c/l-115 case49h/l-4 63 CTCAAAAAAAAAAAAAAAAAAAAA-AAATTCATATTCGCTCATATCAAAAATGAAAATTT gnl | t i I 563501071/127-787 CTCAAAAAAAAAAAGAAAAAAATTCAAATTCATATTCACTCATTTCAAAAATGAAAATTT case49c/l-115 TCATTTC case49h/l-463 ATTTTTGCAAATTTCTA AGTGATAGAATTATTTTAATGTAGGAAAGG-TTCATCAA gnl|ti1563501071/127-787 ATTTTTGCAAATTTCTATTTGAGTGATAGAATTATTTTAATTTAGGAATGGCTTCATAAA case49c/l-115 AAATTTCTATCTGAGTGATAGAATTATTTTAATGTAGGAAAGG-TTCATCAA case49h/l-463 AA gnl|ti|563501071/127-787 AA case49c/l-115 AA Chrl9:46430068=4 64303 97:scaffold_37543:147 6014:-. . .precise d e l e t i o n of AluSq i n chimpanzee CLUSTAL case50h/l-4 95 AGAGTAGGGAATATTCGCTAGAA GGATATATTACAACCCAGATGAGCTAGACCCAGC g n l | t i I 502904367/30-527 ACAGTAGGGAATATTTGCTAGAATGAGGATATATTACAACCCAGATGAGCTAGACCCAGA case50c/l-166 AGAGTAGGGAATATTTGCTAGAA GGATATATTACAACCCAGATGAGCTAGACCCAGC case50h/l-4 95 CTCTGCCCTCAAGTTGCTCCTAGAATAAGAAAACCAAAACCAGGCCAGGTGTGGTGGCTT gnl|ti|502904367/30-527 CTCTGCCCTCAAGTTCCTCCTAGAGTAAGAAAACTAAAACCAGGCCAGCTGTGGTGGCTT case50c/l-166 CTCTGCCCTCAAGTTGCTCCTAGAATAAGAAAACCAAAACCA case50h/l-4 95 ACACCTGTAACCCCAGCACTTTGGGAGGCCAAGGCTGGTGGATCACCTGAGGTCAGGAGT gnl|ti|502904367/30-527 ACACCTATAACCCCAGCACTTTGGGAGGCCACGGCGGGTGGATCACCTGAGGTCAGGAGT case50c/l-166 case50h/l-495 TCGAGACCAGCCTGGCTAACATGGTGAAACCCCATTTCTACTAAAAATACAAAAAATTAG gnl|ti|502904367/30-527 TCGAGACCAGCCTGGCTAACATGGTGAAACCCCATTTCTACTAAAAATACAAAAAATTAG case50c/l-166 case50h/l-495 CCGGGTGTGGTGGCACACACCTGTAATCCCAGCTACTCAGGAGGCTGAGGCAGGAGAATC gnl|ti|502904367/30-527 CCAGGTGTGGTGGCACACACCTGTAATCCCAGCTACTCGGGAGGCTGAGGCAGGAGAATC case50c/l-166 case50h/l-4 95 CCTTGAACCCTGGAGGCAGAGGTTGCAGTGAGCCGAGATCGTGCCATTGCACTCCAGCTT g n l | t i I 502904367/30-527 ACTTGAACCTGGGAGGCAGAGGTTGCAGTGAGCCAAGATTGTGCCATTGCACTCCAGCTT case50c/l-166 case50h/l-4 95 GGGTAACACGAGCGAACTTCCGTCTCAAGAAAAAAAAAAAAAGAAAGAAAGAAAGAAGAA gnl | t i | 502904367/30-527 GGGTAACAAGAGCGAACGTCCGTCTCAAAAAAAAAAAAAAAAAAAAGACAGAAAGAAGAA case50c/l-166 ; 168 case50h/l-495 AACCAAAACCAAAACAAAACTCACAGATCTGTAAATATAAGGCCTAATTCTGGTCTGAAG g n l | t i I 502904367/30-527 AACCAAAACCAAAACCAAATTCACAGATCTGTAAATATAAGGCTGAATTCTGGTCTGAAG case50c/l-166 AAACAAAACTCACAGATCTGTAAATATAAGGCCTAATTCTGGTCTGAAG case50h/l-495 TTCTCTGAGATTAGAAAG g n l I t i I 502904367/30-527 TTCTCTGAGATTAGAATG case50c/l-166 TTCTCTGAGATTAGAAAG chr20:41311768:41311810:scaffold_37443:5951986:-...L2 element tandemly d u p l i c a t e d region i n human, chimp, and rhesus CLUSTAL case51c/l-100 GCCTTTTCAGGGGACTTGACCTCAGCTGGAGACTTTGCTTCTTCCTT g n l | t i I 545384313/363-522 TCCTTCTCTGGGGACTTGGCCTTCTCGGGGGACTTTGCTTCCTCCTTCGTTGGGGACTTG case51h/l-142 GCCTTTTCAGGGGACTTGACCTCAGCTGGAGACTTTGCTTCTTCCTT case51c/l-100 CACTGAGGACTTG g n l | t i I 545384313/363-522 GCCTTTTCAGGGGACTTGGCCTCAGCCGGTGACTTTGCTTCTTCCTTCACTGGGGACTTG case51h/l-142 CACTGGGGACTTGGCCTCAGCTGGTGACTTTGCTTCTTCCTTCACTGGGGACTTG case51c/1-100 GCCTTCTCTGGAGACTTGGCCTCAGCTGATGATTTTGCCT gnl|ti|545384313/363-522 GCCTTCTCTGGAGACTTGGCCTCAGCTGGTGACTTTGCCT case51h/1-142 GCCTTCTCTGGAGACTTGGCCTCAGCTGGTGATTTTGCCT chr22:45658137:45658441:scaffold_37534:1549045:-. . .precise d e l e t i o n of AluSq i n chimpanzee CLUSTAL case52h/l-458 CTGCTTAACCAGATGAGGAAGAACGAGGTTAATGAAAATGCCCAGTGATGGTGACGGTAA g n l | t i I 555960713/344-767 CTGCTTAACCAAATGAGGGAGAACAAGG AAATGCCCAGTGATTGTGAGGGTAA case52c/l-154. CTGCTTAACCAGATGAGGAAGAACGAGGTTAATGAAAATGCCCAGTGATGGTGAGGGTAA case52h/l-458 AGAAATGCCCCCTCTCGGCCAGGCGCGGTGGCTCATGTCTGTAATCCCAGCACCCTGGGG g n l | t i I 555960713/344-767 AGAAATGCCCCCTCTCGGCCGGGCACGGTGGCTCACACCTGTAATCCCAGCACTTTGGGA case52c/l-154 AGAAATGTCCCCTCTC case52h/l-458 GGCCGAGGCGGGCGGATCACTTGAGGTCAGGAGTTTGAGACCAGCCTGGCCAACAGGGTG gnl|ti|555960713/344-767 GGCCGAGGCAGGCGGATAACCTGAGGTCAGGAGTTCGAGACCAGCCTGGCCAACATGGTG case52c/l-154 case52h/l-458 AAACCCCGTCTCTACTAAAAAATACAAAAATTAGCCAGGCGTGGTGGCAGGCGCCTTAAT g n l | t i I 555960713/344-767 AAACCCTGTCTCTACTAAAAAATAGAAAAATTAGCTGGGCGTGGTGGCAGGAGCTTTAAT case52c/l-154 case52h/l-458 CCTAGCTACTTGGGAGGCAGAGGCAGGAGAATCGTTTGAACCCAGGAGGCAGAGGTTGCA gnl | t i I 555960713/344-767 CCCAGCTACTTGGGAGGC GGAGGCAGAGGTTGCA case52c/l-154 case52h/l-458 GTGGGCTGAGATCGAGCCACTGCACTCAAGCCTGGGGGACAAGGGCGAGACTTCTCTGAA gnl|ti|555960713/344-767 GTGAGGCAAGATCGAGCCATTGCACTCAAGCCTGGGGGACAAGGGTGAGACTTCTGTCAA case52c/l-154 case52h/l-458 AAAAGGAAATGCCCCCTCTCACAAAACTGCTGGCTGCAGGGCAAACCAACTCAGTGGGCC gnl|ti|555960713/344-767 AAAAG-AAATGTCCCCTCTCACAAAATTGCTGGCTGCCCGGCAAACCAACTCAGTGGGCC case52c/l-154 ACAAAATTGCTGGCTGCAGGGCAAACCAACTCAGTGGGCC case52h/l-458 CCAGGGTCACTTGGCTGTGGCCACCAAGTTCCCCAAAC gnl|ti|555960713/344-767 CCAGGGTCACTTGGCCGTGTGCACCAAGTTCCACAAAC case52c/l-154 CCAGGGTCACTTGGCTGTGGCCACCAAGTTCCTCAAAC chr22:46857451:4 6857769:scaffold_37534:338287:-169 ...AluY p a r t i a l l y deleted and reversed i n Rhesus ( s l i g h t l y complicated example of NHEJ), gene conversion to AluYa5 i n human, pr e c i s e d e l e t i o n i n chimpanzee CLUSTAL case53h/l-418 GGCACTGGACCAAGCCTTCCTGCTGGGCAGAGATGGGACTGGCTTTTCATAAGATTGCGC gnl|ti|556293551/420-813 GGCAGTGGACCAAGCCTTCCTGCCGGGCAGAGACGGGACTGGC case53c/l-100 GGCACTGGACCAAGCCTTCCTGCTGGGCAGAGACGGGACTGGCTTTTCATAAGATTGAGC case53h/l-418 CTTGGGCCGGGCACGGTGGCTCACTCCTGTAATCCCAGCACTTTGGGAGGCCGAGGCGGG gnl | t i I 556293551/420-813 XXATGAAAAGCCAGXXTCCCAGCACTTTGGGAGGCCGAGACGGG case53c/l-100 CTT case53h/l-418 CGGATCACGAGGTCAGGAGATCGAGACCATCCCGGCTATAACGGTGAATCCCCGTCTCTA gnl|ti|556293551/420-813 CGGATCACGAGGTCAGGAGATCGAGACCATCCTGGCTAACACGGTGAAACCCCGTCTCTA case53c/l-100 case53h/l-418 CTA-AAAATACAAAAAA-TTAGCCGGGCGTAGTGGCGGGCGCCTGTAGTCCCAGCTACTT g n l | t i I 556293551/420-813 CTACAAAATACAAAAAAACTAGCCGGGCGAGGTGGCGGGCACCTGTAGTCCCAGCTACTC case53c/l-100 case53h/l-418 GGGAGGCTGAGGCAGGAGAATGGCGTGAACCCGGGAGGCGGAGCTTGCAGTGAGCCGAGA gn l | t i I 556293551/420-813 GGGAGGCTGAGGCAGGAGAATGGCGTGAACCTGGGAGGCGGAGCTTGCAGTGAGCTGAGA case53c/l-100 case53h/l-418 TCCCGCCACTGCACTCCAGCCTGGGCGACAGAGCGAGACTCCGTCTCAAAAAAAAAAAAA gn l | t i I 556293551/420-813 TCCGGCCACTGTACTCCAGCCTGGGCCACAGAGCGAGACTCCGTCTCAAAAAAAAAAAAA case53c/l-100 case53h/l-418 ACAAAAAAAA AAGATTGCGCCTTTCAGCAACATCAACTCTTCCAGGAAATGTG gnl|ti|556293551/420-813 AAAAAAAAAAGAAAAXXAAGATTGTGCCTTTCAGCAACATCGAGTCTTCCAGGAAATGTG case53c/l-100 TCAGCAACATCAACTCTTCCAGGAAATGTG case53h/l-418 CTTATAT gnl|ti|556293551/420-813 CTTACAT case53c/l-100 CTTATAT chrX:5202006:52022 92:scaffold_25582:6996:-... pre c i s e d e l e t i o n of AluSp i n chimpanzee CLUSTAL case54h/l-431 TGGAAGCCTGACCAGAAAATATCATGGCATCAGTTCAACGCATCCCAAAAACTCACTTAA gnl|ti|485777938/470-934 TGGCAGCCTGACCAGAAAATATGATGGCATCAGTTCAACGCATCCCAAAAACTCACTTAA case54c/l-140 TGGTAATCTGATCAGAAGATATCA CAGTACAACGCATCCCAAAAACTCACTTAA case54h/l-431 AAGCCAAAGGCAGGCCGGGCGTGGTGGCTCACGCCTATAATCCCAGCACTTTGGGAGGCC gnl|ti|485777938/470-934 AAGCCAAAGGCAGGCCGGGAATGGTGGCTCACGCCTATAATCCCAGCACTCTGGGAGGCC case54c/l-140 AAGCTAAAGGCA case54h/l-431 GAGGCAGGTGGATCACCTGAGGTCGGGAGTTCAAGACCAGCCTGACCAACATGGAGAAAT gnl|ti1485777938/470-934 GAGGCAGGTGGATCACCTGAGGTCGGGAGTTCAAGACCAGCCTGACCAACATGGTGAAAC case54c/l-140 case54h/l-431 CCCATCTCTACTAAAAATACAAAATTAGCCAGGTGTGGTGGCACATGCCTGTAATCCCAG gnl|ti1485777938/470-934 CCCATCTTTACTAAAATTACAAAATTAGCTGGGTGTGGGGGCACATGCCTGTAATCCCAG case54c/l-140 case54h/l-431 CTACTCGGGAGG CTGAGGCAGGAGAATGGCTTGAACCTGGGAGGGGGAGGCTGCAGT gnl | t i | 485777938/470-934 CTACTCGGGAGGAGGCTGAGGCAGGAGAATGGCTTGAACCTGGGAGGCAGAGGCTACGGG case54c/l-140 case54h/l-431 GAGCGAAACTC CATC AAAAAAAAAAA AAA gnl|ti|485777938/470-934 GGGCCAAGATCGCGCCATTGCACTCCAGACTGGGCAACAAGAGGGAAACTCCGTTTCAAA case54c/l-140 case54h/l-431 AAAAAGGAAAGAAAAAAAAAAGCCAAAGACAAACAAATCATCTGACAGCTGCAAAGAAAA gnl | t i | 485777938/470-934 AAAAAAAAAAAAAAAAAAAATACCAAAGGCAAACAAATCATCTGACATCTGCAAAGAAAA case54c/l-140 AAC AAATC AGCTGACGTCTGC AAAT AAAC 170 case54h/l-431 GTGCAAGTCCCTATGTTTTGTTTTGTTTTTCATTCTATTTCCAGA gnl|ti|485777938/470-934 GTGCAAGTCCCTATGTTTTGTTTTGTTTTTCATTCTATTTCCAGA case54c/l-140 ATGCAAGTCTCTATGTTTTGTCTTGGTTTTCACCCTATCTCCAGA chrX:86865679:86865830:scaffold_37382:835478:+ ...imprecise d e l e t i o n of low complexity region i n chimpanzee, no f l a n k i n g i d e n t i t y CLUSTAL case55h/l-251 GTAATAGA ATAGGAAAAGTTTATTTCTTATTCTTAAAGATGAATCATTTAGAA gnl Iti1495823394/144-417 GTAATATACAGTGTAATAGGAAAAGTTTATTTCTTACTCTTAAAGATGAATCATTTGGAA case55c/l-100 GTAATAGA ATAGGAAAAGTTTATTTCTTATTCTTACAGATGAATCATTTA case55h/l-251 CAAAAATTTTTGCTTTTTCTTTTAGAATATATATATGTGTGTATATATATGT g n l | t i I 495823394/144-417 CAA—ATTTTTGCTTTTTCTTTTAGAATATATATGTGTGTGTATATATATGTGTGTGTAA case55c/l-100 case55h/1-251 ATATATGTGTGTGTATATATATGTATATATATGTGTGTGTATATATATAT gnl|ti|495823394/144-417 ATGTGTGTATATGTGTATGTGTGTGTATATATGTGTATGTATATATGTGTGTGTGTATGT case55c/l-100 case55h/l-251 GTGTATATATATGTACTGAAGCATATTCTCAAAATGTGCAAAGAGGCTGCAGTAATATTA gnl|ti|495823394/144-417 GTGTATATATAAGCACTAAAGCATATTCTCAAAATGTGCAAAGAGGCTGCAGTAATATTA case55c/l-100 CTGCAGTAATATTA case55h/l-251 TAGATAATTAAAATGAGTCAAACTCTGATTTTGAGG gnl|ti|495823394/144-417 TGGATAAGTAAAATGAGTCAAACTCTGATTTTGAGG case55c/1-100 TTGATAATTAAAATGAGTCAAACTCTGATTTTGAGG Primers and Sequences >caseCl_3 GTACAGTT GAGGC AT T GCT AC >caseCl_5 TCAGTCTCCAGGGAAGCAATG >caseC2_3 AGGCAATAAAAGAGGCCGGCT >caseC2_5 CAGAGCTCTTTCCTTCCACTC >caseC3_3 TGGGTTATAGGCTTACAGATG >caseC3_5 GAGATAGGCCAAGAACTATAG >caseC4_3 AGAGTACCACCAAGGTATTAG >caseC4_5 GAACTGATGTCTGCAACTTTG >casel4_3 CATACACATATAAGACCCTTC >casel4_5 GTCTCAGTGATAACTTGATGA >case33_3 TTGTAGGGTTGAGAGAGCCTC . >case33_5 TGGCCACTTACCTTCTGCTTC >case42_3 CTTTCTGTCTTATGGGAACTC >case42_5 GAACATCTCTATTCACCTTCG >case43_3 TTAGTGCAGGATGAAGTTGGC >case43_5 TTCTCCCATCTGGTCATGTGA >case52_3 CAGAAAGACACCATGGGTGAA >case52_5 GCCTGTGGATAGATCATAGTC 171 


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