Worm Breeder's Gazette 3(1): 26
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 have been analyzing the lineage and morphology of ts embryonic- arrest mutants. It is possible to classify the mutants into four major groups according to their lethal phenotype: 1. mutants arrested before the first division, 2. mutants arrested during the proliferation period (1-cell to around lima bean stage with ca. 540 cells ), 3. mutants arrested around the lima bean stage, the beginning of morphogenetic period, 4. mutants arrested during morphogenesis (lima bean stage to hatching ) . The majority of the mutants studied belong to the 3rd group. Interestingly, all the mutants of this group have visible morphological abnormalities much earlier (before about the 80-cell stage) than at their arrested stage. Parameters such as cell division axes, division rhythm of stem cell groups, and size of sister cells are essentially invariant in the wild-type embryo (1) . One or more of these parameters are affected in the mutants of the 3rd group.