Identification of Genes Affecting Sexual Dimorphism of the Gonad in Caenorhabditis Elegans
Gold, Alexandra P.
Caenorhabditis elegans is an excellent system for the study of both organogenesis and genetics due a variety of phenotypic features, including its transparent body, short generation time and self-fertile hermaphrodite. As a result, the worm's developmental trajectory is well understood and the genome was completely sequenced by 1998. Recent research has focused on the complex signaling pathways controlling sex determination and the development of the gonad. In this study, we used an F2 modifier screen to explore the genetic controls of gonadogenesis and used balancer strains to determine the location of the mutations found in the screen. To increase the likelihood of male-specific gonad defects arising from the mutagenesis, we used worms carrying two mutations: q626ts, an allele of unnamed locus that causes unorganized and non-extended gonads in the male, and him-5(eI490), which induces ~ 33 % male progeny rather than the spontaneous 0.2 % from hermaphrodite self-fertilization. After screening the progeny from 598 mutagenized hermaphrodites, we found three mutations causing gonad defects, designated q768, q769, and q770. Using balancer strains, we determined that none of the novel mutations were on the portions of chromosomes I, II or III that are balanced by the hT2 and mIn1 alleles. Additionally, by removing q626ts from the background, we determined that each mutation acts in concert with q626ts rather than having an independent phenotype. Further research will determine the location of each mutation in the genome and other allelic characteristics, including to which gene each mutation corresponds, illuminating the role of those genes in gonadogenesis.
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