The Drosophila sex determination gene daughterless has different functions in the germ line versus the soma.
As a regulator of the female-specific gene Sxl, da+ provides an essential maternal component in the control of sex determination and dosage compensation; nevertheless, neither the maternal nor zygotic phenotypes of the original mutant da allele is sex-specific. Here we clarify the role of da+ in Drosophila development, finding: this sex determination gene is indeed pleiotropic; zygotic functioning of da+ is essential in both sexes for somatic cell development, but not for germ cell development; da female sterility results from a somatic, rather than germ-line, defect; and expression of da+ in the maternal germ line is required only for daughters in the subsequent generation, as expected for a specific regulator of Sxl+. These conclusions follow from the characterization of new da null alleles isolated by a selection for defects in maternally acting positive regulators of Sxl.
D000483:Alleles; D000818:Animals; D004330:Drosophila / Q000166:cytology / Q000196:embryology / Q000235:genetics*; D000078404:Epidermal Cells; D005260:Female; D005796:Genes; D005854:Germ Cells / Q000166:cytology; D006720:Homozygote; D008297:Male; D009154:Mutation; D010641:Phenotype; D012732:Sex Determination Analysis