Interaction of the mutants sx, tra and dsx in Drosophila melanogaster. Chaetotaxy of the basitarsus of the forelegs in males and females

Abstract

The basitarsal bristle pattern of the mutants sx (sexcombless), tra (transformer), and dsx (doublesex), and of the combinations sx-dsx and tra-dsx is described. Epistasis of dsx over both sx and tra for many of the chaetotaxal characteristics was found. The various effects of interaction observed, in individuals of male as well as female chromosomal constitution, are discussed in the light of the levels of action of the mutant genes in modifying the development of sex. It is suggested that intersexes induced by dsx are a class by itself, and that the action of dsx might be at a primary level of sex determination.