Molecular organization of the alcohol dehydrogenase loci of Drosophila grimshawi and Drosophila hawaiiensis.

To determine sequences involved in conserved and species-specific aspects of alcohol dehydrogenase (Adh) gene expression in Hawaiian Drosophila, a 3644-base pair (bp) region containing the D. grimshawi gene and the homologous 3335-bp region containing the D. hawaiiensis Adh gene were sequenced. These genes have the two-promoter and exon-intron structure seen for many Drosophila Adh genes. Analysis of putative and known regulatory sequences of the D. grimshawi and D. hawaiiensis genes in comparison to those of D. affinidisjuncta (the only other Hawaiian species for which the promoter organization is known) highlighted elements likely to be involved in conserved aspects of Adh gene expression as well as sequences that may account for species-specific differences in tissue-specific expression. Sequence comparisons, in the context of regulatory roles previously assigned to particular gene fragments, indicated that multiple insertions and deletions in the promoter regions are responsible for differences in tissue-specific regulation displayed by these genes.