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).

Caenorhabditis
Caenorhabditis elegans
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Nematoda
Class: Chromadorea
Order: Rhabditida
Family: Rhabditidae
Genus: Caenorhabditis
Osche, 1952[1]
Synonyms

Rhabditis (Caenorhabditis) Osche, 1952

The genus Caenorhabditis 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).[2]

C. elegans is the type species of the genus.[3] In 1900, Maupas initially named the species Rhabditis elegans, Osche placed it in the subgenus Caenorhabditis in 1952, and in 1955, Dougherty raised Caenorhabditis to the status of genus.[4]

Ecology

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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.[5]

Species

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Cladogram of Caenorhabditis species
Caenorhabditis
Species of Caenorhabditis: C. nigoni is the sister species of C. briggsae while C. elegans stays alone, basal in the 'Elegans' group.

There are about 50 known species in this genus, some of them not yet formally described and named,[6] in spite of 15 of the species being named in one article 2014.[7] Based on ITS2 sequence comparison, these can be grouped like this:[7]

Other phylogenetic studies

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The Caenorhabditis species group with the 'Protorhabditis' group, containing species in the genera Protorhabditis, Diploscapter and Prodontorhabditis, on the one hand, and with Oscheius species, on the other hand, to form the 'Eurhabditis' group of Rhabditidae genera.[25]

Members of Caenorhabditis exclusively share 39 conserved signature indels that are found in the conserved regions of various proteins, such as the Rab44 protein and a poly ADP-ribose glycohydrolase protein (PARG-1), and are specifically located on surface-exposed loops.[26] These molecular markers help distinguish this genus from all other species, and their presence on surface-exposed loops suggest implications in protein-protein or protein-ligand interactions.[26]

References

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  1. ^ Osche, G., 1952.— “Systematik und Phylogenie der Gattung Rhabditis (Nematoda)”. Zool. Jb. (Abt. 1), 81, 190–280.
  2. ^ Haag, Eric S. (2005). "The evolution of nematode sex determination: C. elegans as a reference point for comparative biology". WormBook: The Online Review of C. Elegans Biology. WormBook: 1–14. doi:10.1895/wormbook.1.120.1. PMC 4781019. PMID 18050417.
  3. ^ Caenorhabditis at nematode.unl.edu
  4. ^ Ellsworth C. Dougherty (1955) The Genera and Species of the Subfamily Rhabditinae Micoletzky, 1922 (Nematoda): a Nomenclatorial Analysis—including an Addendum on the Composition of the Family Rhabditidae Örley, 1880. Journal of Helminthology 29(3): 105-152 doi:10.1017/S0022149X00024317
  5. ^ Kiontke, K; Sudhaus, W (Jan 2006). "Ecology of Caenorhabditis species". WormBook: 1–14. doi:10.1895/wormbook.1.37.1. PMC 4780885. PMID 18050464.
  6. ^ 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. PMC 3277298. PMID 22103856.
  7. ^ a b c d e f g h i j k l m n o p q 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. 9 (4): e94723. Bibcode:2014PLoSO...994723F. doi:10.1371/journal.pone.0094723. PMC 3984244. PMID 24727800.
  8. ^ "NCBI". Retrieved 23 June 2017.
  9. ^ The C. elegans Sequencing Consortium (1998). "Genome sequence of the nematode C. elegans: a platform for investigating biology". Science. 282 (5396): 2012–2018. Bibcode:1998Sci...282.2012.. doi:10.1126/science.282.5396.2012. PMID 9851916.
  10. ^ "Wormbase". Retrieved 4 September 2015.
  11. ^ 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.
  12. ^ "Wormbase". Retrieved 4 September 2015.
  13. ^ "GSC: Caenorhabditis remanei". Archived from the original on 13 March 2007. Retrieved 28 April 2007.
  14. ^ "Wormbase". Retrieved 4 September 2015.
  15. ^ "GSC: Caenorhabditis n. sp. PB2801". Archived from the original on 18 August 2007. Retrieved 28 April 2007.
  16. ^ "Wormbase". Retrieved 4 September 2015.
  17. ^ "GSC: Caenorhabditis japonica". Archived from the original on 28 February 2008. Retrieved 28 April 2007.
  18. ^ "WormBase". Retrieved 4 September 2015.
  19. ^ "Genome Institute". Archived from the original on 9 October 2015. Retrieved 4 September 2015.
  20. ^ "Wormbase". Retrieved 7 September 2015.
  21. ^ "Wormbase". Retrieved 7 September 2015.
  22. ^ 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.
  23. ^ 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.
  24. ^ "Wormbase". Retrieved 4 September 2015.
  25. ^ The phylogenetic relationships of Caenorhabditis and other rhabditids. Karin Kiontke and David H. A. Fitch, Wormbook, 2005, doi:10.1895/wormbook.1.11.1
  26. ^ a b Khadka, Bijendra; Chatterjee, Tonuka; Gupta, Bhagwati P.; Gupta, Radhey S. (2019-09-24). "Genomic Analyses Identify Novel Molecular Signatures Specific for the Caenorhabditis and other Nematode Taxa Providing Novel Means for Genetic and Biochemical Studies". Genes. 10 (10): 739. doi:10.3390/genes10100739. ISSN 2073-4425. PMC 6826867. PMID 31554175.