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Molecular evolutionary studies on the chlorarachniophyte : Bigelowiella natans Rogers, Matthew Brian
Abstract
Chlorarachniophytes are marine cercozoan amoeboflagellates with plastids derived from a secondary endosymbiotic event involving a green alga. The retention of a vestigial eukaryotic nucleus, or 'nucleomorph' in the plastid of chlorarachniophytes makes chlorarachniophytes ideal organisms for the study of secondary endosymbiosis. Among chlorarachniophytes, the majority of sequence data are from a single species, Bigelowiella natans. Thousands of expressed sequence tags and a complete nucleomorph and chloroplast genome from Bigelowiella natans provide a detailed picture of genes encoding proteins with function in the plastid of chlorarachniophytes. The phylogeny of three plastid-targeted Calvin cycle enzymes with complicated distributions and multiple recompatmentalisation events are described. These three enzymes are also the only known Calvin cycle enzymes in B. natans that show any evidence of having been acquired through endosymbiotic gene transfer. Previous studies have detailed the contribution of lateral gene transfer to the plastid function of B. natans. Several specific examples of these events are expanded on and discussed. Plastid-targeting peptides from published sequences are characterized and a heterologous targeting experiment in to the apicoplast of Toxoplasma gondii is described. The complete plastid genome of Bigelowiella natans has been sequenced. This plastid genome appears to be the smallest among all known photosynthetic plastid genomes, though it nevertheless retains most of the photosynthesis related genes present in chlorophytes. Phylogenetic analysis of concatenated chloroplast protein coding genes indicates that the endosymbiont of B. natans may be a derived green algae, and argues strongly against a single origin of chlorarachniophyte and euglenids plastids predicted by the cabozoa hypothesis.
Item Metadata
Title |
Molecular evolutionary studies on the chlorarachniophyte : Bigelowiella natans
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Creator | |
Publisher |
University of British Columbia
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Date Issued |
2006
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Description |
Chlorarachniophytes are marine cercozoan amoeboflagellates with plastids
derived from a secondary endosymbiotic event involving a green alga. The retention of a
vestigial eukaryotic nucleus, or 'nucleomorph' in the plastid of chlorarachniophytes
makes chlorarachniophytes ideal organisms for the study of secondary endosymbiosis.
Among chlorarachniophytes, the majority of sequence data are from a single species,
Bigelowiella natans. Thousands of expressed sequence tags and a complete nucleomorph
and chloroplast genome from Bigelowiella natans provide a detailed picture of genes
encoding proteins with function in the plastid of chlorarachniophytes. The phylogeny of
three plastid-targeted Calvin cycle enzymes with complicated distributions and multiple
recompatmentalisation events are described. These three enzymes are also the only
known Calvin cycle enzymes in B. natans that show any evidence of having been
acquired through endosymbiotic gene transfer. Previous studies have detailed the
contribution of lateral gene transfer to the plastid function of B. natans. Several specific
examples of these events are expanded on and discussed. Plastid-targeting peptides from
published sequences are characterized and a heterologous targeting experiment in to the
apicoplast of Toxoplasma gondii is described. The complete plastid genome of
Bigelowiella natans has been sequenced. This plastid genome appears to be the smallest
among all known photosynthetic plastid genomes, though it nevertheless retains most of
the photosynthesis related genes present in chlorophytes. Phylogenetic analysis of
concatenated chloroplast protein coding genes indicates that the endosymbiont of B.
natans may be a derived green algae, and argues strongly against a single origin of
chlorarachniophyte and euglenids plastids predicted by the cabozoa hypothesis.
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Genre | |
Type | |
Language |
eng
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Date Available |
2011-02-03
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Provider |
Vancouver : University of British Columbia Library
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Rights |
For non-commercial purposes only, such as research, private study and education. Additional conditions apply, see Terms of Use https://open.library.ubc.ca/terms_of_use.
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DOI |
10.14288/1.0100504
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URI | |
Degree | |
Program | |
Affiliation | |
Degree Grantor |
University of British Columbia
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Campus | |
Scholarly Level |
Graduate
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Aggregated Source Repository |
DSpace
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Rights
For non-commercial purposes only, such as research, private study and education. Additional conditions apply, see Terms of Use https://open.library.ubc.ca/terms_of_use.