Fig. 4. Early lineage of Z1 or Z4 in wild-type and pop-1 defective animals. (A-D) Vertical lines represent cells; horizontal lines represent divisions. Z1/Z4 represents Z1 or Z4; left daughter is distal; right daughter is proximal. DTC, distal tip cell; AC/VU, anchor cell or ventral uterine precursor; LC/VD, linker cell or vas deferens precursor. Only cell divisions in L1 and L2 were observed. (A) Wild-type hermaphrodite. The distal daughter divides once and gives rise to a DTC; the proximal daughter divides twice and gives rise to an AC/VU. (B) pop-1(q645). Two hermaphrodites were watched from hatching until L2 lethargus. Z1/Z4 distal daughters divided twice, in three out of four cases; no DTCs were made. (C) Wild-type male. The distal daughter does not divide and becomes a DTC; the proximal daughter divides twice and gives rise to an LC/VD. (D) pop-1(RNAi) male. Z1/Z4 distal daughters both migrated anteriorly and divided once, albeit later than their proximal sisters. Later divisions were not followed.