Worm Breeder's Gazette 2(2): 23a
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 shall summarize our work on selecting and characterizing X-ray- induced chromosomal duplications. We have also isolated X-ray-induced deletions of bits of the X chromosome covered by Dp(X;V)1. We have further characterized two X-ray-induced crossover suppressors for linkage group II. One, called C1, is coupled to dpy-10 and unc-52, is homozygous viable, and segregates independently of all other linkage groups: it is probably an intrachromosomal rearrangement. We have used a C1 dpy-10 unc-4 stock to identify over 100 EMS induced recessive lethal mutations coupled to unc-4 and balanced by the C1 chromosome. About half of the lethals are embryonic or larval. The rest give sterile adults, some of which are rescuable by mating with wild-type males. Some of the lethals have been complemented and mapped. They tend to map in the cluster of visibles. Tetraploid stocks, one of which is homozygous for unc-3 and dpy-11, have been established. In agreement with Nigon's earlier work, we find that tetraploid hermaphrodites are either high frequency male producers (giving roughly 45% males) or low (giving less than 1%). Triploids can be produced by crossing tetraploid males by diploid hermaphrodites or vice versa. Triploid hermaphrodites have small brood sizes and lay many eggs that do not hatch. Our results are consistent with the following genotypic assignments (where A denotes one set of autosomes): 4X/4A, low frequency male producer; 3X/4A, high frequency male producer; 2X/4A, male; 2X/3A, male.