Heterozygotes are WT and segregate WT, DpySteriles and Uncs which produce only dead eggs at 25C but viable progeny at 15C. Throws males.

This strain can grow at 11.5C but is embryonic lethal at 15C and above. Temperature shifts in late embryogenesis or in larval stages result in defects in many asymmetric cell divisions in postembryonic develoment.