Worm Breeder's Gazette 7(1): 46
These abstracts should not be cited in bibliographies. Material contained herein should be treated as personal communication and should be cited as such only with the consent of the author.
We've finished determining the P. redivivus postembryonic nongonadal cell lineages. The postembryonic nongonadal increases in nuclear number in P. redivivus (P.r.) and C. elegans (C.e.) are as follows. [See Figure 1] The additional blast cells in P. redivivus are two intestinal cells and a rectal cell K2 (a.k.a. K') and a tail ectoblast T3. Four cells present in both sexes divide only in the males of both species. Most of the additional cells generated in P. redivivus are derived from the lateral hypodermal precursors (V1-V6). The extra deaths of the P. redivivus female are found in the M and P lineages. There is variability in the lateral hypodermal lineages in P. redivivus. The male tails of P. redivivus and C. elegans differ substantially in gross morphology: C. elegans, but not P. redivivus, males have a bursal fan; the spicules are shaped differently; and P. redivivus has 14 knob-like caudal papillae rather than 18 elongated caudal papillae ( rays). In P. redivivus males, each V6 cell generates four caudal papillae precursors (Rn cells) and T1 and T2 each generate three Rn cells. In C. elegans, each V5 generates one, each V6 generates five and each T cell generates three Rn cells. The Rn sublineage is identical in the two species. The lineages of the male-specific blast cells (B, Y, U and F) differ only by one extra round of cell division in the F lineage and certain division axes in the B, Y and F lineages. As homologous structures in the two species have essentially the same number of cells, the morphological differences are probably caused by differences in the morphogenetic programs of lineally equivalent cells.