Studies on the sex-specific lethals of Drosophila melanogaster. V. Sex transformation caused by interactions between a female-specific lethal, Sxlf 1, and the male-specific lethals mle(3)132, msl-2(27), and mle.

Interactions between a female-specific lethal mutant, Sxlf 1, and each of three male-specific lethal mutants, mle(3)132, msl-2(27) and mle, of Drosophila melanogaster were observed to produce morphological changes in various sexually dimorphic external characters. Chromosomal females heterozygous for Sxlf 1 and homozygous for any one of the male-specific lethals (and to a lesser degree heterozygous for male-specific lethals) sometimes had sex combs, male-type tergites, male-type sternites, male-type anal plates or male-type external genitalia. Penetrance was not high and expression was often incomplete; single individuals never had all the sexually dimorphic structures transformed. When mothers were homozygous for male-specific lethals, higher proportions of female progeny were affected than when mothers were heterozygous, suggesting a maternal effect.