Probable evolutionary mechanism underlying octanol dehydrogenase isozyme patterns in the genus drosophila.

A comparative species study of octanol dehydrogenase (ODH) isozyme patterns of members of the genus Drosophila and six related genera has shown a rough correlation of these with taxonomic grouping at the level of subgenus or section within the subgenera Pholadoris, Sophophora, and Drosophila. Extensive polymorphism of ODH patterns occurs in the quinaria section of the subgenus Drosophila. In polymorphic strains of D. pellewae and D. metzii, ODH pattern types of single females were shown to occur in frequencies expected on the hypothesis of a Hardy-Weinberg distribution of morphs depending on alleles at a single locus. However, patterns of homozygous B and A variants extracted from such populations differ from those expected if variants are due to alleles at a structural locus and indicate that such variants differ in alleles affecting the levels of particular isozymes. ODH patterns of monomorphic species strikingly resemble those of homozygous B, D, or A variants extracted from polymorphic populations of D. pellewae, D. metzii, or D. albirostris which have been studied genetically by Pipkin (1968a, 1969) and Ogonji (1971). Based on these findings and previous work indicating that the ODH molecule is a polymer, an hypothesis is proposed that species differences in ODH patterns depend on differential activity of several ODH structural genes. [ABSTRACT FROM AUTHOR]