OMIA:001199-10141 : Coat colour, extension in Cavia porcellus (domestic guinea pig)
In other species: lorises , coyote , dog , red fox , American black bear , domestic cat , jaguar , ass (donkey) , horse , Przewalski's horse , pig , Arabian camel , reindeer , taurine cattle , indicine cattle (zebu) , goat , sheep , rabbit , Mongolian gerbil , domestic yak , fallow deer , alpaca , gray squirrel , raccoon dog , antarctic fur seal , woolly mammoth , rock pocket mouse , oldfield mouse , lesser earless lizard , Geoffroy's cat , jaguarundi , Colocolo , little striped whiptail , water buffalo , Arctic fox
Categories: Pigmentation phene
Links to MONDO diseases: No links.
Mendelian trait/disorder: yes
Mode of inheritance: Autosomal recessive
Considered a defect: no
Key variant known: yes
Year key variant first reported: 2018
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 the MC1R gene in brown, black and bi-colour guinea pigs, Vidal (2018) identified one brown allele (e; MC1R*2) as c.749T>C, p.Leu250Gln and another brown allele (e; MC1R*4) as "a deletion of 2760 bp, including the entire MC1R coding region".
Have human generated variants been created, e.g. through genetic engineering and gene editing
|Symbol||Description||Species||Chr||Location||OMIA gene details page||Other Links|
|MC1R||Cavia porcellus||-||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|
|1007||Brown coat colour||MC1R||e (MC1R*4)||deletion, gross (>20)||Naturally occurring variant||Vidal (2018): "a deletion of 2760 bp, including the entire MC1R coding region"||2018||30101449|
|1006||Brown coat colour||MC1R||e (MC1R*2)||missense||Naturally occurring variant||c.749T>C||p.(L250Q)||2018||30101449|
Cite this entry
Note: the references are listed in reverse chronological order (from the most recent year to the earliest year), and alphabetically by first author within a year.
|2018||Vidal, O. :|
|Deleterious mutations of MC1R in guinea pig. Anim Genet , 2018. Pubmed reference: 30101449. DOI: 10.1111/age.12708.|
|1996||Cone, RD., Lu, D., Koppula, S., Vage, DI., Klungland, H., Boston, B., Chen, W., Orth, DN., Pouton, C., Kesterson, RA. :|
|The melanocortin receptors: agonists, antagonists, and the hormonal control of pigmentation. Recent Prog Horm Res 51:287-317; discussion 318, 1996. Pubmed reference: 8701084.|
|1919||Ibsen, H.L. :|
|Tricolor Inheritance. IV. the Triple Allelo-Morphic Series in Guinea-Pigs. Genetics 4:597-606, 1919. Pubmed reference: 17245939. DOI: 10.1093/genetics/4.6.597.|
|1916||Ibsen, H.L. :|
|Tricolor Inheritance. I. the Tricolor Series in Guinea-Pigs. Genetics 1:287-309, 1916. Pubmed reference: 17245859. DOI: 10.1093/genetics/1.3.287.|
- Created by Frank Nicholas on 18 Jul 2010
- Changed by Frank Nicholas on 12 Oct 2011
- Changed by Frank Nicholas on 17 Aug 2018
- Changed by Frank Nicholas on 20 Aug 2018