Heterozygotes are Unc and segregate Uncs, dead eggs and abc-1 homozygotes. At 25C abc-1 homozygotes are sterile Unc animals. At 16C abc-1 homozygotes are fertile animals that produce all dead eggs.

Temperature sensitive - maintain at 16C. L1 shift-up to 25C produces incompletely penetrant sterile Unc phenotype. L4 shift-up produces leaky Mel phenotype.

Temperature sensitive - maintain at 16C. L1 shift-up to 25C produces incompletely penetrant sterile Unc phenotype. L4 shift-up produces Mel phenotype.

Temperature sensitive - maintain at 16C. L1 shift-up to 25C produces incompletely penetrant sterile Unc phenotype. L4 shift-up produces Mel phenotype.

Temperature sensitive - maintain at 16C. L1 shift-up to 25C produces sterile, slightly Unc animals. L4 shift-up produces Mel phenotype.

Temperature sensitive - maintain at 16C. L1 shift-up to 25C sterile Unc animals. L4 shift-up produces Mel phenotype.

Heterozygotes are WT and segregate WT, dead eggs and Uncs. At 25C the Unc Spds are Sterile; at 16C the Unc Spds are fertile but produce mostly dead eggs. Unc Spd animals will exhibit a fully penetrant maternal-effect embryonic lethal phenotype if shifted to 25C at the L4 stage. unc-13 spd-2 homozygotes may be propagated at 16C but may become sick causing immense frustration! See also WBPaper00004200.