Presumptive control mutation for alcohol dehydrogenase in Drosophila melanogaster

Abstract

EXAMPLES of control mutations are rare in eukaryotes. Indeed, the only well-documented examples are in Aspergillus1,2 and a mutant affecting xanthine dehydrogenase (XDH) activity and mapping adjacent to, but separable from, rosy, the structural gene for XDH in Drosophila melanogaster3,4. Control of alcohol dehydrogenase (ADH), particularly in Drosophila has recently been studied. In examining ADH activity in selection lines and in samples from natural populations, a line was found to be Adhs and to have half the activity of a normal slow-migrating allele. To test the hypothesis that the low activity Adhs line contains a control mutation, we have attempted to separate the activity phenotype from the electrophoretic (structural gene) phenotype by recombination. We have succeeded in doing this, and in the process have obtained a very accurate position for Adh based on its recombination with closely-linked marker loci.