From Wikipedia, the free encyclopedia
Jump to: navigation, search
Adult Caenorhabditis elegans.jpg
Caenorhabditis elegans
Scientific classification
Kingdom: Animalia
Phylum: Nematoda
Class: Secernentea
Order: Rhabditida
Family: Rhabditidae
Genus: Caenorhabditis

Caenorhabditis is a genus of nematodes which live in bacteria-rich environments like compost piles, decaying dead animals and rotting fruit. The name comes from Greek: caeno- (καινός (caenos) = new, recent); rhabditis = rod-like (ῥάβδος (rhabdos) = rod, wand). The Caenorhabditis genus contains the noted model organism Caenorhabditis elegans and several other species for which a genome sequence is either available or currently being determined. The two most-studied species in this genus (C. elegans and C. briggsae) are both androdioecious (they have male and hermaphrodite sexes) whereas most other species are gonochoristic (they have male and female sexes).[1]


Caenorhabditis occupy various nutrient and bacteria rich environments. They do not form self-sustaining populations in soil, as it lacks enough organic matter. Juvenile worms and also dauer larvae can be transported by invertebrates including millipedes, insects, isopods, and gastropods. Some species also appear to be associated with vertebrates including zebu cattle, although the nature of this association is not clear. The species can be classified as 'phoretic' or 'necromenic' based on their relationships to their invertebrate hosts. A phoretic worm rides on the host until it finds a favorable environment, and then leaves. A necromenic worm waits for the host to die, and lives on the bacteria which thrive in the dead animal. Many species are capable of both phoretic and necromenic lifestyles.[2]


Known species in this genus include:[3]

  • Caenorhabditis briggsae - genome sequence finished 2003 at Washington University in St. Louis.[6] C. briggsae is the second-best studied species in the genus. While C. briggsae are also mostly XX protandrous hermaphrodites, they are not the closest relatives to C. elegans, and the hermaphroditic reproductive strategy of these species, as well as C. tropicalis, is an example of convergent evolution. The evolutionary distance between C. briggsae and C. elegans is similar to that of humans and mice. C. nigoni is the closest relative of C. briggsae, and the two species can occasionally produce somewhat fertile hybrids.[7]
  • Caenorhabditis remanei - genome sequenced by WashU GSC.[8] More closely related to C. briggsae than C. elegans, C. remanei is a gonochoristic (male-female obligate) species in the Elegans group. In the past, there was some confusion about placement of strains between C. remanei, C. vulgaris (now seen as a subspecies of C. remanei) and C. brenneri"". [9]
  • Caenorhabditis brenneri - (prior to 2007 referred to as C. sp 4, C. sp CB5161, and C. sp PB2801) - genome sequenced by WashU GSC.[10] This gonochoristic species is found in the Elegans group, closer to C. briggsae than C. elegans.[11]
  • Caenorhabditis japonica - genome being sequenced by WashU GSC. [12] This gonochoristic species is found in the Japonica group, the sister clade to the Elegans group. In the wild, this species is found non-parasitically associated with the burrower bugs Parastrachia japonensis and may be able to enter the dauer stage regardless of food and crowding conditions.[13][14]
  • Caenorhabditis angaria - (prior to 2011 referred to as C. sp. 2, C. sp. 3, and C. sp. PS1010)[15] - genome sequenced at the California Institute of Technology in 2010.[16] This gonochoristic species, found in the Angaria group of the Drosophilae super-group, has distinct morphology and behavior compared to C. elegans. Notably, C. angaria males exhibit a spiral mating behavior. Its divergence from C. elegans is similar to the distance between humans and fish. C. castelli is its closest relative, and the two species can produce F1 hybrids.[17]


  1. ^ Haag, Eric S. "The evolution of nematode sex determination: C. elegans as a reference point for comparative biology". WormBook. 
  2. ^ Kiontke, K; Sudhaus, W (Jan 2006). "Ecology of Caenorhabditis species.". WormBook: 1–14. doi:10.1895/wormbook.1.37.1. PMID 18050464. 
  3. ^ Kiontki, Karin; et al. (November 21, 2011). "A phylogeny and molecular barcodes for Caenorhabditis, with numerous new species from rotting fruits". BMC Evolutionary Biology 11: 339. doi:10.1186/1471-2148-11-339. Retrieved 6 February 2012. 
  4. ^ The C. elegans Sequencing Consortium (1998). "Genome sequence of the nematode C. elegans: a platform for investigating biology". Science 282 (5396): 2012–2018. doi:10.1126/science.282.5396.2012. PMID 9851916. 
  5. ^ "Wormbase". Retrieved 4 September 2015. 
  6. ^ Stein, L. D.; et al. (2003). "The Genome Sequence of Caenorhabditis briggsae: A Platform for Comparative Genomics". PLoS Biology 1 (2): 166–192. doi:10.1371/journal.pbio.0000045. PMC 261899. PMID 14624247. 
  7. ^ "Wormbase". Retrieved 4 September 2015. 
  8. ^ "GSC: Caenorhabditis remanei". Archived from the original on 13 March 2007. Retrieved 28 April 2007. 
  9. ^ "Wormbase". Retrieved 4 September 2015. 
  10. ^ "GSC: Caenorhabditis n. sp. PB2801". Archived from the original on 18 August 2007. Retrieved 28 April 2007. 
  11. ^ "Wormbase". Retrieved 4 September 2015. 
  12. ^ "GSC: Caenorhabditis japonica". Archived from the original on 28 February 2008. Retrieved 28 April 2007. 
  13. ^ "WormBase". Retrieved 4 September 2015. 
  14. ^ "Genome Institute". Retrieved 4 September 2015. 
  15. ^ Sudhaus, Walter; Kiontke, Karin; Giblin-Davis, Robin M. (2011). "Description of Caenorhabditis angaria n. sp. (Nematoda: Rhabditidae), an associate of sugarcane and palm weevils (Coleoptera: Curculionidae)". Nematology 13 (1): 61–78. doi:10.1163/138855410X500334. Retrieved 7 September 2015. 
  16. ^ Mortazavi, A.; Schwarz, E. M.; Williams, B.; Schaeffer, L.; Antoshechkin, I.; Wold, B. J.; Sternberg, P. W. (2010). "Scaffolding a Caenorhabditis nematode genome with RNA-seq". Genome Research 20 (12): 1740–1747. doi:10.1101/gr.111021.110. PMC 2990000. PMID 20980554. 
  17. ^ "Wormbase". Retrieved 4 September 2015. 
  18. ^ "Wormbase". Retrieved 7 September 2015. 
  19. ^ a b c d e f g h i j k l m n o Félix, Marie-Anne; Braendle, Christian; Cutter, Asher D. (April 11, 2014). "A Streamlined System for Species Diagnosis in Caenorhabditis (Nematoda: Rhabditidae) with Name Designations for 15 Distinct Biological Species". PLOS ONE. doi:10.1371/journal.pone.0094723. Retrieved 7 September 2015. 
  20. ^ "Wormbase". Retrieved 7 September 2015.