Structural analysis of the ADHS electromorph of Drosophila melanogaster.

Abstract

Population geneticists have often determined the fitness differences that account for the dynamics of naturally occurring genetic polymorphisms. To understand causal aspects of evolutionary processes also requires investigation of the physiological and molecular structural differences underlying adaptively significant genetic polymorphisms. The characteristics of the alcohol dehydrogenase gene-enzyme system in D. melanogaster make it well suited for this kind of study. Natural populations of this species are polymorphic for 2 electrophoretically detectable variants, ADHF and ADHS, of the enzyme. Structural studies reported here reveal that the 2 variants differ by (at least) a single amino acid replacement, threonine in ADHF for lysine in ADHS.