OMIA:001199-37190 : Coat colour, extension in Arctocephalus gazella
In other species: taurine cattle , dog , horse , red fox , pig , sheep , jaguar , jaguarundi , American black bear , woolly mammoth , domestic cat , rabbit , domestic guinea pig , goat , Arctic fox , rock pocket mouse , oldfield mouse , gray squirrel , lesser earless lizard , little striped whiptail , water buffalo , domestic yak , alpaca , coyote , reindeer , Geoffroy's cat , Colocolo , ass (donkey) , Arabian camel , Mongolian gerbil , raccoon dog , fallow deer , indicine cattle (zebu) , lorises , Przewalski's horse
Categories: Pigmentation phene
Links to MONDO diseases: No links.
Mendelian trait/disorder: yes
Mode of inheritance: Autosomal recessive
Considered a defect: unknown
Key variant known: yes
Year key variant first reported: 2016
Cross-species summary: The extension locus encodes the melanocyte-stimulating hormone receptor (MSHR; now known as MC1R). This receptor controls the level of tyrosinase within melanocytes. Tyrosinase is the limiting enzyme involved in synthesis of melanins: high levels of tyrosinase result in the production of eumelanin (dark colour, e.g. brown or black), while low levels result in the production of phaeomelanin (light colour, e.g. red or yellow). When melanocyte-stimulating hormone (MSH) binds to its receptor, the level of tyrosinase is increased, leading to production of eumelanin. The wild-type allele at the extension locus corresponds to a functional MSHR, and hence to dark pigmentation in the presence of MSH. As explained by Schneider et al. (PLoS Genet 10(2): e1004892; 2015), "The most common causes of melanism (black coat) mutations are gain-of-function alterations in MC1R, or loss-of function alterations in ASIP, which encodes Agouti signaling protein, a paracrine signaling molecule that inhibits MC1R signaling". Mutations in MC1R have been associated with white colouring in several species.
Molecular basis: "By sequencing 70 wild-type individuals with dark-colored coats and 26 hypopigmented individuals with cream-colored coats, we [Peters et al., 2016)] identified a nonsynonymous mutation that results in the substitution of serine with phenylalanine at an evolutionarily highly conserved structural domain. All of the hypopigmented individuals were homozygous for the allele coding for phenylalanine, consistent with a recessive loss-of-function allele."
|Symbol||Description||Species||Chr||Location||OMIA gene details page||Other Links|
|MC1R||Arctocephalus gazella||-||no genomic information (-..-)||MC1R||Ensembl|
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WARNING! Inclusion of a variant in this table does not automatically mean that it should be used for DNA testing. Anyone contemplating the use of any of these variants for DNA testing should examine critically the relevant evidence (especially in breeds other than the breed in which the variant was first described). If it is decided to proceed, the location and orientation of the variant sequence should be checked very carefully.
Since October 2021, OMIA includes a semiautomated lift-over pipeline to facilitate updates of genomic positions to a recent reference genome position. These changes to genomic positions are not always reflected in the ‘acknowledgements’ or ‘verbal description’ fields in this table.
|OMIA Variant ID||Breed(s)||Variant Phenotype||Gene||Allele||Type of Variant||Source of Genetic Variant||Reference Sequence||Chr.||g. or m.||c. or n.||p.||Verbal Description||EVA ID||Inferred EVA rsID||Year Published||PubMed ID(s)||Acknowledgements|
|1346||Hypopigmentation (blond)||MC1R||missense||Naturally occurring variant||c.872C>T||p.(S291F)||2016||27547348|
Cite this entry
|2016||Peters, L., Humble, E., Kröcker, N., Fuchs, B., Forcada, J., Hoffman, J.I. :|
|Born blonde: a recessive loss-of-function mutation in the melanocortin 1 receptor is associated with cream coat coloration in Antarctic fur seals. Ecol Evol 6:5705-17, 2016. Pubmed reference: 27547348 . DOI: 10.1002/ece3.2290.|
- Created by Frank Nicholas on 13 Sep 2021