fog-1, a regulatory gene required for specification of spermatogenesis in the germ line of Caenorhabditis elegans

Genetics. 1990 May;125(1):29-39.


In wild-type Caenorhabditis elegans, the XO male germ line makes only sperm and the XX hermaphrodite germ line makes sperm and then oocytes. In contrast, the germ line of either a male or a hermaphrodite carrying a mutation of the fog-1 (feminization of the germ line) locus is sexually transformed: cells that would normally make sperm differentiate as oocytes. However, the somatic tissues of fog-1 mutants remain unaffected. All fog-1 alleles identified confer the same phenotype. The fog-1 mutations appear to reduce fog-1 function, indicating that the wild-type fog-1 product is required for specification of a germ cell as a spermatocyte. Two lines of evidence indicate that a germ cell is determined for sex at about the same time that it enters meiosis. These include the fog-1 temperature sensitive period, which coincides in each sex with first entry into meiosis, and the phenotype of a fog-1; glp-1 double mutant. Experiments with double mutants show that fog-1 is epistatic to mutations in all other sex-determining genes tested. These results lead to the conclusion that fog-1 acts at the same level as the fem genes at the end of the sex determination pathway to specify germ cells as sperm.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Alleles
  • Animals
  • Caenorhabditis / genetics*
  • Caenorhabditis / physiology
  • Chromosome Mapping
  • Epistasis, Genetic
  • Female
  • Genes
  • Genes, Regulator*
  • Genotype
  • Male
  • Mutation
  • Organ Specificity / genetics
  • Phenotype
  • Sex Determination Analysis*
  • Spermatogenesis / genetics
  • Temperature