Table 1.
Mutations with effects on mating system dynamics in Caenorhabditis elegans
| Gene | Function | Mating system effect | Functional background | Evolutionary applications |
| fog-2 | F-box protein that binds tra-2 mRNA before sexual maturity, thereby initiating germ-line production of sperm in hermaphrodites. | Mutants do not undergo protandrous production of sperm, effectively feminizing hermaphrodites, leading to dioecy and obligate outcrossing. | Schedl and Kimble (1988); Clifford et al. (2000); Nayak et al. (2005) | Stewart and Phillips (2002); Katju et al. (2008); Morran, Parmenter, et al. (2009) |
| him-5 | Influences the number and distribution of X chromosome pairing events; molecular function currently unknown. | Causes X-specific nondisjunction and so leads to high frequency of males. | Hodgkin et al. (1979); Broverman and Meneely (1994) | Chasnov and Chow (2002); Cutter and Payseur (2003) |
| spe-8 | Protein tyrosine kinase involved in the sperm activation signaling pathway. | Produces nonfunctional sperm in hermaphrodites, leading to dioecy. | L'Hernault et al. (1988); Muhlrad and Ward (2002) | LaMunyon and Ward (2002); LaMunyon et al. (2007) |
| spe-26 | Actin-binding protein needed for normal spermatogenesis. | Effects as in spe-8. | Varkey et al. (1995); Minniti et al. (1996) | Cutter (2005) |
| tra-2 | Membrane-bound protein that controls trafficking of the sex determination signaling pathway. | Mutants transform hermaphrodites into males. A temperature-sensitive version can be used to mimic temperature-dependent sex determination, such as that found in turtles. | Hodgkin and Brenner (1977); Kuwabara et al. (1992); Kuwabara and Kimble (1995); Hodgkin (2002) | Janzen and Phillips (2006); Chandler et al. (2009) |
| tra-3 | Regulatory protease that cleaves tra-2. | Can delay the transition between sperm and egg production in hermaphrodites, thereby shifting the pattern of sex allocation. | Hodgkin and Brenner (1977); Sokol and Kuwabara (2000) | Hodgkin and Barnes (1991) |
| xol-1 | Metabolic kinase that helps assess the X/autosome ratio and regulates X chromosome dosage compensation. | Mutants disrupt dosage compensation, which leads to male (XØ) lethality and results in obligate selfing. | Miller et al. (1988); Rhind et al. (1995) | Morran, Parmenter, et al. (2009) |