Worm Breeder's Gazette 2(2): 16
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.
A recessive temperature-sensitive mutant has been isolated which produces a sexually dimorphic phenotype at 25 C-hermaphrodites are sterile and males become intersexes. The mutant is designated tsH17; gene intersex-1 (isx-1), and maps 4.8+1.0% to the right of dumpy-13 on chromosome IV. At 16 C tsH17 hermaphrodites produce nearly wild-type numbers of progeny (250) and are morphologically normal. Males are also morphologically normal, produce fertile sperm and mate properly. At 25 C mutant hermaphrodites produce no sperm but are otherwise normal and make oocytes which may be fertilized by wild-type males. In the absence of mating, however, only a few oocytes are made (10-15 per animal) and these are laid as endoreduplicated, unfertilized eggs. Restrictively grown animals with a single X chromosome are intersexes rather than males. These animals have normal male somatic structures including: bursae, diagonal muscles and anterior sensory nerves and exhibit a rudimentary mating behavior. Intersex gonads are variable in morphology from male-like to hermaphrodite-like and contain oocytes or abortive gametes but usually no sperm. Vulvas or abortive vulvas are present in nearly half of all intersexes. Their frequency of appearance and degree of normality correlate with the degree of 'hermaphrodicity' of the underlying gonad in a manner consistent with an inductive mechanism of vulva formation. The various phenotypes of tsH17 have not been separated by recombination and a revertant has been isolated which partially corrects all of the mutant phenes examined. Thus the pleiotropic effects all appear to be due to a single lesion. The temperature sensitive periods for the various phenes differ but overlap. All precede the last moult. Experiments are now in progress to examine the interactions between intersex and mutant alleles of the two transformer genes tra-1, and tra-2.