C. elegans is a free-living, non-parasitic soil nematode
that can be found throughout the world. It is transparent and about 1mm in size. “Worm” is its nickname. Researchers working with C. elegans call themselves “worm people” and form the “worm community” of research.
C. elegans feeds on bacteria (such as E. coli) or anything else that fits in its mouth. Video of a worm eating.
There are two sexes, hermaphrodite and male. 1 2
Hermaphrodite
Hermaphrodite (color diagram)
Male
C. elegans has five pairs of autosomes and one pair of sex chromosome. Sexual determination in C. elegans is similar to Drosophila; the ratio of sex chromosomes
to autosomes determines its sex. If the 6th chromosome pair is XX, then C. elegans will be a hermaphrodite. A XO combination in the 6th chromosome pair will produce a male. XO combination in male is the spontaneous loss of X chromosome (XX -> XO). When a male crosses with a hermaphrodite, the progeny
will be half males and half hermaphrodites
.
Hermaphrodites can self-fertilize or cross with males. However, hermaphrodites cannot fertilize another hermaphrodite. Males can only cross with hermaphrodites. Crossing between a male and hermaphrodite produces more progeny than the self-fertilization of a hermaphrodite (about 350 progeny). 3
Its life cycle and life span are about 3 days and 3 weeks, respectively.