Females homozygous for scM6 fail to activate the SxlPe (establishment) promoter and subsequently die from dosage compensation upsets.
Hemizygous scM6 flies are sterile and lack some sensory bristles. scM6/+ female flies have a very low frequency of missing anterior postalar and posterior supra-alar bristles.
At 18oC 12% of expected scsisB-2 homozygotes survive to adulthood, but this drops to less than 0.2% when these animals are raised at 25oC. In contrast, hemizygous males are fully viable. With variable penetrance scM6 homozygous adults lack all dorsal head bristles apart from the posterior vertical bristles, and all bristles of the dorsal thorax apart from the posterior notoplural, posterior dorsocentral and scutellar bristles. With variable penetrance scM6/In(1)sc8Lsc4R adults lack all dorsal head bristles apart from the anterior vertical bristles, and all bristles of the dorsal thorax apart from the dorsocentral and bristles. With variable penetrance scM6/Df(1)sc19 adults lack all dorsal head bristles and all dorsal thoracic bristles.
The bristle phenotype seen female D.simulans/D.melanogaster hybrids is unaffected by the addition of scM6 at 18oC. At 25oC there is a small general low level increase in bristle loss.
Homozygous embryos develop MP2 neuroblast normally.
Females are lethal, most likely because of the absence of sc+ function in the blastoderm. Homozygotes display a reduction in the presence of certain notum bristles. In an ac- background (In(1)y3PLsc8R) the phenotype was improved, only the anterior dorsocentral bristle, posterior supraalar bristle and microchaetae are reduced in numbers.