Heterozygotes are WT and segregate WT, Dpy Steriles and ceh-13 homozygotes which are dead eggs and deformed embryos.

Egl, Pvul, Psa (Phasmid Socket Absent) and some embryonic lethality. The T cell division can be symmetric as in lin-17 mutants. Less severe at 15C. swsn-4 encodes a homolog of yeast SW12, a component of the SWI/SNF complex.

Temperature sensitive. At 22.5C, maternal effect embryonic lethal. Temperature shift-up to 22.5C during embryogenesis results in animals with Egl, Pvul and Psa (phasmid socket absent) phenotypes. Shift-up to 25C results in growth arrest at larval stage. The T cell division can be symmetric as in lin-17 mutants. At 15C, nearly WT. Males grown at 15C can mate very well. psa-1 encodes a homolog of yeast SW13, a component of the SWI/SNF complex. Sequence data of this strain revealed the mutation is actually GTC/CCC/TCA to GTC/CTC/TCA causing a P86L substitution (G. Hayes).