Evidence for a Genetic Duplication involving Alcohol Dehydrogenase Genes in Drosophila huzzatii and Related Species

Abstract

Drosophila buzzatii has two closely linked loci (0· 4 ± O· 3 cM apart) encoding NAD + -dependent alcohol dehydrogenase. These two loci produce complex, non-overlapping electrophoretic phenotypes and differ in their ontogenetic expression, that of Adh-l relative to Adh-2 being less in adults than in third-instar larvae. Isozymes produced by the two Adh-2 alleles analysed have similar in vitro ADH activity levels, substrate specificities and thermostabilities, whereas the isozymes of the two Adh-l alleles examined differ in ADH activity and specificity for primary versus secondary alcohol substrates.