UBC Theses and Dissertations
Molecular analysis of the Drosophila gene, Polyhomeotic Freeman, Sally Jean
Polyhomeotic (ph) is a developmentally important gene in Drosophila melanogaster which has been genetically characterized and recently cloned. ph is genetically and molecularly complex and has a strong maternal effect. Analysis of null or amorphic alleles reveal phenotypic effects that include embryonic lethality, cell death of the ventral epithelium, homeotic transformations, and alteration in the pattern of axon pathways. Two independent point mutations are required to produce a ph null allele. I have shown that the ph locus contains two, large, highly conserved, tandem repeats that are both transcribed. I have identified transcripts that are altered in ph mutants and that are developmentally regulated. Fourteen cDNA's have been isolated, and mapped. Northern and Southern blot analysis, and comparisons between cDNA and genomic restriction maps shows that the cDNAs represent at least 4 different transcripts that include distinct products of both repeats as well as non-repeated sequence. Both the genetic behavior and molecular organization of the ph locus are unique in Drosophila.
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