The Genetics and Cell Biology of Fertilization - Caenorhabditis Elegans: Molecular Genetics and Development - page 341

molecules have been implicated in fertilization across a wide evolutionary spectrum,
from HrVC70 in ascidians ( Sawada et al., 2004 ) to SPE-9 in worms ( Singson et al.,
1998 ) and SED-1 in mammals ( Ensslin and Shur, 2003 ).
In this chapter, we introduce the major experimental approaches/implications to
consider when using C. elegans to study fertilization. A general scheme for the study
of sterility mutants in C. elegans is presented in Fig. 4 . Detailed protocols can be
found in the original literature and in L ' Hernault and Roberts (1995) .
Fig. 2 Examples of the sterile phenotypes observed when fertilization or proper egg activation does not
occur. (A) In wild-type hermaphrodites, embryos (black arrows) can be observed developing in the uterus.
(B) Oblong shelled embryos (black arrows) are laid at the 50+ cell stage and ultimately hatch into larvae
(white arrow). (C) In sterile mutants (e.g., spe-9(hc52) shown here) unfertilized oocytes (black arrows) are
seen in the uterus. (D) These soft, flattened, and opaque unfertilized oocytes (black arrows) are also laid.
(E) Egg-activation mutants (e.g., spe-11(hc77) shown here) lay more rounded thinly shelled eggs or
''pebbles'' (black arrows) that neither develop nor hatch.