The Drosophila melanogaster alcohol dehydrogenase gene (adh) is under the control of two separate promoters (proximal and distal) which are preferentially utilized at the larval and adult life stages, respectively. A variant alcohol dehydrogenase allele (RI-42) isolated from a natural population contains a copia retroviral-like transposable element inserted 240 bp upstream from the distal (adult) adh transcriptional start site. Levels of adh transcripts in the RI-42 variant are reduced in tissues and at life stages where copia is actively expressed and are affected in trans- by mutant alleles at the suppressor-of-white-apricot (su(wa] and suppressor-of-forked (su(f] loci. These suppressor genes have no effect on adh expression in wild-type Drosophila.