Fig. 7.

T-seam-cell lineages in wild-type and nhr-25(ku217)-mutant hermaphrodites. The directions of cell divisions are shown with anterior to the left. (A) Wild-type T-seam-cell lineage. Blue circles mark hypodermal cells that join the hyp7 syncytium; green triangle labels a seam cell; yellow rectangles indicate phasmid socket cells; and red rectangles show other neurons. X represents programmed cell death. (B-E) Both sides of five nhr-25(ku217) mutants were analyzed. Seven out of the ten T-seam-cell lineages exhibited abnormal cell division pattern (B-E). All of them showed a T.pa cell with hypodermal morphology and without subsequent division, resulting in Psa (phasmid-socket absent) phenotype. Three nhr-25(ku217) lineages displayed only Psa phenotype (B). In one case, T.pp underwent a division producing two neural cells, but without further division of the posterior daughter (C). Failure of T.pp cell division was noticed in three lineages, of which in one case the T.pp cell exhibited neural morphology (D), whereas in two cases it adopted hypodermal morphology (E). The anterior lineages, indicated by dotted lines, were followed until T.ap had divided, at which time all the cells showed hypodermal character.