Structural and genetic studies of the proliferation disrupter genes of Drosophila simulans and D-melanogaster

To examine whether structural and functional differences exist in the proli feration disrupter (prod) genes between Drosophila simulans and D. melanoga ster, we analyzed and compared both genes. The exon-intron structure of the genes was found to be the same - three exons were interrupted by two intro ns, although a previous report suggested that only one intron existed in D. melanogaster. The prod genes of D. simulans and D. melanogaster both turn out to encode 346 amino acids, not 301 as previously reported for D. melano gaster. The numbers of nucleotide substitutions in the prod genes was 0.074 7 +/- per synonymous site and 0.0116 +/- 0.0039 per replacement site, both comparable to those previously known for homologous genes between D. simula ns and D. melanogaster. Genetic analysis demonstrated that D. simulans PROD can compensate for a deficiency of D. melanogaster PROD in hybrids. The PR ODs of D. simulans and D. melanogaster presumably share the same function a nd a conserved working mechanism. The prod gene showed no significant inter action with the lethality of the male hybrid between these species.