Free-living, transparent nematode, about 1 mm in length, which lives in temperate soil environments. Research into the molecular and developmental biology of C. elegans was begun in 1974 by Sydney Brenner, and C. elegans has since been used extensively as a model organism. C. elegans is one of the simplest organisms with a nervous system. The organism has also been used as a model for nicotine dependence, as it has been found to experience the same symptoms humans experience when they quit smoking.
A roundworm, about 1 mm long. It is the first multicellular organism for which the full genome was sequenced. Its cells are used in studies of the molecular basis of development, aging, and fat metabolism.