Fig. 3. Unlike da null alleles, da^lyh completely complements stl^a16. DAPI stained ovarioles dissected from various da mutant genotypes. (A) Ovaries of flies doubly heterozygous for stl^a16 and the null allele da² contain severe morphological defects in all ovarioles. (B) Similar defects are present in ovarioles that are doubly heterozygous for stl^a16 and the hypomorph das22. (C) By contrast, da^lyh completely complements stl^a16. (D) In 15% of ovarioles from flies with an ectopic copy of da⁺, mild defects include mislocalization of the oocyte nucleus (arrow). The remaining 85% of the ovarioles are completely normal, indicating that the wild-type allele of da does not have to be on the homologous chromosome to provide full function. In each panel, the anterior end of the ovariole is at the top.