OMIA 001199-30538 : Coat colour, extension in Vicugna pacos
In other species: 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 , , coyote , reindeer , Geoffroy's cat , Colocolo , ass , Arabian camel , Mongolian gerbil , raccoon dog , fallow deer , zebu Possibly relevant human trait(s) and/or gene(s)s (MIM numbers): 266300 (trait) , 155555 (gene) , 203200 (trait) Mendelian trait/disorder: yes Mode of inheritance: Autosomal Considered a defect: no Key variant known: no 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. Markers: Investigating the effect of 18 SNPs within the MC1R gene in black, brown, cream and white alpacas, Guridi et al. (2011) were not able to discover any causative SNPs for any of the coat colours. They did, however, find three SNPs associated with colour lightness.
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.
|2015||Chandramohan, B., Renieri, C., La Manna, V., La Terza, A. :|
|The alpaca melanocortin 1 receptor: gene mutations, transcripts, and relative levels of expression in ventral skin biopsies. ScientificWorldJournal 2015:265751, 2015. Pubmed reference: 25685836. DOI: 10.1155/2015/265751.|
|2011||Guridi, M., Soret, B., Alfonso, L., Arana, A. :|
|Single nucleotide polymorphisms in the Melanocortin 1 Receptor gene are linked with lightness of fibre colour in Peruvian Alpaca (Vicugna pacos). Anim Genet 42:679-82, 2011. Pubmed reference: 22035014. DOI: 10.1111/j.1365-2052.2011.02205.x.|
|2009||Feeley, N.L., Munyard, K.A. :|
|Characterisation of the melanocortin-1 receptor gene in alpaca and identification of possible markers associated with phenotypic variations in colour Animal Production Science 49:675–681 , 2009.|
|2008||Powell, A.J., Moss, M.J. , Tree, L.T. , Roeder, B.L. , Carleton, C.L. , Campbell, E. , Kooyman, D.L. :|
|Characterization of the effect of Melanocortin 1 Receptor, a member of the hair color genetic locus, in alpaca (Lama pacos) fleece color differentiation Small Ruminant Research 79:183-187, 2008.|
- Created by Frank Nicholas on 02 Nov 2011
- Changed by Frank Nicholas on 02 Nov 2011
- Changed by Frank Nicholas on 06 Dec 2011