Maleless, a recessive autosomal mutant of Drosophila melanogaster that specifically kills male zygotes.

A second chromosome male-specific lethal gene, maleless (mle), in D. melanogaster is described. It kills males but not females in homozygous condition, regardless of whether female parents are heterozygous or homozygous for mle. Many, if not most, homozygous males survive up to the third instar larval stage, but cannot pupate and die eventually as larvae. No interactions with sex-transforming genes, tra and dsx, were observed. It is proposed that mle interacts with a gene(s) on the X chromosome, which is not dosage compensated.