Temperature-dependent transformation from male to female external cuticle phenotype. Expression of tra^hs.PB female specific product in Sxl^M1,fPa-ra individuals causes the external sexually dimorphic cuticle of male flies to develop with a female morphology, the muscle phenotype remained male-like.

Hemizygous males are viable at 22^oC or 25^oC. When in trans with a copy of Sxl⁺ viability is dramatically reduced at 25^oC and the same at 22^oC.

This complex allele disrupts both male and female development, with the magnitude of the effects in either sex depending on culture temperature in a reciprocal fashion: high temperature is more permissive for females and less permissive (more feminizing) for males. Intersexual males show little male sexual behavior and stimulate courtship from other males. Dominant male-lethal effects are greatly enhanced by the presence of a duplication of Sxl⁺ in trans; male escapers with both alleles exhibit an unusual dorsalization of the abdomen, their sternites being variably transformed into tergites. complex partial revertant of Sxl^M1,fPa complementing Sxl^f9; male ts; female cs