Heterozgyotes are WT and segregate WT, Uncs which give only dead eggs, and dead eggs.

Heterozygotes are WT and segregate WT and Uncs. The Uncs have a non-conditional maternal-effect embryonic lethal phenotype: the E blastomere adopts MS fate in about 5% of mutant embryos. The Uncs are 100% penetrant for embyronic lethality and morphogenesis defects.