Organization and evolution of the alcohol dehydrogenase gene in Drosophila

The alcohol dehydrogenase (Adh) gene was isolated from Drosophila simulansand D. mauritiana, and the DNA sequence of a 4.6-kb region, containing thestructural gene and flanking sequence, was determined for each. Thesesequences were compared with the Adh region of D. melanogaster tocharacterize changes that occur in the Drosophila genome during evolutionand to identify conserved sequences of functional importance. Drosophilasimulans and D. mauritiana Adh are organized in a manner similar to that ofD. melanogaster Adh, including the presence of two promoters for the singleAdh gene. This study identified conserved flanking elements that, inconjunction with other studies, suggest regions that may be involved in thecontrol of Adh expression. Inter- and intraspecies comparisons revealeddifferences in the kinds of sequence changes that have accumulated.Sequence divergence in and around the Adh gene was used to assess inter-and intraspecies evolutionary relationships. Finally, there appears to bean unrelated structural gene located directly 3' of the Adh transcribedregion.