Western clawed frog
Western clawed frog | |
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Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Class: | Amphibia |
Order: | Anura |
Family: | Pipidae |
Genus: | Xenopus |
Species: | X. tropicalis
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Binomial name | |
Xenopus tropicalis (Gray, 1864)
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Synonyms | |
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The western clawed frog (Xenopus tropicalis) is a species of frog in the family Pipidae, also known as tropical clawed frog.[2] It is the only species in the genus Xenopus to have a diploid genome.[3][4] Its genome has been sequenced,[5][6] making it a significant model organism for genetics that complements the related species Xenopus laevis (the African clawed frog),[7] a widely used vertebrate model for developmental biology. X. tropicalis also has a number of advantages over X. laevis in research, such as a much shorter generation time (<5 months), smaller size (4–6 cm (1.6–2.4 in) body length), and a larger number of eggs per spawn.[8]
It is found in
Description
The western clawed frog is a medium-sized species with a somewhat flattened body and a snout-vent length of 28 to 55 mm (1.1 to 2.2 in), females being larger than males. The eyes are bulging and situated high on the head and there is a short tentacle just below each eye. A row of unpigmented dermal tubercles runs along the flank from just behind the eye, and are thought to represent a lateral line organ. The limbs are short and plump, and the fully webbed feet have horny claws. The skin is finely granular. The dorsal surface varies from pale to dark brown and has small grey and black spots. The ventral surface is dull white or yellowish with some dark mottling.[9]
Distribution and habitat
The western clawed frog is an aquatic species and is found in the West African rainforest belt with a range stretching from Senegal to Cameroon and eastern Zaire. It is generally considered a forest-dwelling species and inhabits slow-moving streams, but it is also found in pools and temporary ponds in the northern Guinea and Sudan savannas.[9]
Biology
In the dry season, this frog lives in shallow streams and hides under tree roots, under flat stones, or in holes in the riverbank. It feeds primarily on earthworms, insect larvae and tadpoles. When the rainy season starts it migrates across the forest floor at night to find temporary pools. Spawning may take place in large pools with much vegetation, but tadpoles are also sometimes found in muddy pools with no vegetation. Single
Sex determination
Although X. tropicalis does have these three sex chromosomes, the frequency of these three sex chromosomes is not evenly distributed among this species' populations throughout its natural range. The Y chromosome has been identified from two localities in Ghana and in a laboratory strain that originated in Nigeria and the Z chromosome has been confirmed to exist in individuals from western and eastern Ghana.[12] Additionally, all three sex chromosomes have been found to exist together in X. tropicalis populations in Ghana and potentially elsewhere in its range as well.[12] Additionally, having irregular sex ratios in offspring is generally thought to be disadvantageous so whether or not the existence of three sex chromosomes in X. tropicalis is evolutionarily stable or an indication that the species is going through a sex chromosome transition (turnover), is still a question.[12] It seems likely that the emergence of the Y chromosome is the most recent event in the evolution of this species' sex chromosomes.[12] It is possible that in the future extinction of the Z chromosome would make it so that the W chromosome transitions into a X chromosome making this species with sex determined by an XY system.[12] It is also possible that if the Y chromosome were to go extinct, this species will have reverted to using an ancestral ZW system.[12]
Status
The
Use as a genetic model system
Xenopus embryos and eggs are a popular model system for a wide range of biomedical research.[3][13] This animal is widely used because of its powerful combination of experimental tractability and close evolutionary relationship with humans, at least compared to many model organisms.[13]
Unlike its sister species X. laevis, X. tropicalis is diploid and has a short generation time, facilitating genetic studies.[3] The complete genome of X. tropicalis has been sequenced.[5] This species has n=10 chromosomes.[14]
X. tropicalis has three
Online Model Organism Database
References
- ^ . Retrieved 11 November 2021.
- ^ Frost, Darrel R. (2014). "Xenopus tropicalis (Gray, 1864)". Amphibian Species of the World: an Online Reference. Version 6.0. American Museum of Natural History. Retrieved 3 March 2015.
- ^ PMID 21963197.
- PMID 9676522.
- ^ PMID 20431018.
- ^ JGI X. tropicalis v4.1
- PMID 17984085.
- ^ "Bringing Genetics To Xenopus: Half The Genome, Twice As Fast". University of Virginia. Retrieved 2009-10-24.
- ^ a b c M. O. Roedel; Vance Vredenburg; M. J. Mahoney; Tate Tunstall; Kellie Whittaker (2010-05-01). "Xenopus tropicalis". AmphibiaWeb. Retrieved 2013-12-06.
- PMID 24983465.
- ^ PMID 26216983.
- ^ PMID 33166278.
- ^ a b Wallingford, J., Liu, K., and Zheng, Y. 2010.Current Biology vol. 20, p. R263–4
- ^ "Xenopus tropicalis (ID 80) - Genome - NCBI". www.ncbi.nlm.nih.gov. Retrieved 2020-12-01.
- PMID 23552219.
- PMID 29059324.
- ^ "Xenopus model organism database". Xenbase.org.
External links
- Xenbase Xenopus model organism database
- View the xenopus genome in Ensembl
- View the xenTro7 genome assembly in the UCSC Genome Browser.