OMIA:000202-452646 : Coat colour, oculocutaneous albinism type I (OCA1), TYR-related in Neovison vison (American mink)
In other species: Japanese medaka , dark-spotted frog , Japanese wrinkled frog , Tufted capuchin , Rhesus monkey , hamadryas baboon , dog , red fox , domestic ferret , domestic cat , lion , humpback whale , ass (donkey) , pig , red deer , American bison , taurine cattle , rabbit , golden hamster , Mongolian gerbil , domestic guinea pig , Japanese ratsnake , water buffalo , four-striped grass mouse , ocelot gecko , Japanese raccoon dog , Rice frog
Categories: Pigmentation phene
Links to MONDO diseases: No links.
Mendelian trait/disorder: yes
Mode of inheritance: Autosomal recessive
Considered a defect: yes
Key variant known: yes
Year key variant first reported: 2008
Cross-species summary: Congenital lack of pigment in most parts of the body. Due to a non-functional form of the enzyme tyrosinase. Also known as Oculocutaneous albinism (OCA), Acromelanism and as the Himalayan coat-colour pattern
Species-specific description: Two mutant alleles have been characterized at the molecular level: albino (complete loss of function) and marbled or Himalayan (temperature-sensitive partial loss of function). The Himalayan phenotype is similar to that of the Siamese and Burmese cats: "light-colored body with dark-colored points (ears, face, tail, and feet)" (Benkel et al., 2009).
Inheritance: The predicted dominance hierarchy is: wildtype > Himalayan > albino
Mapping: Anistoroaei et al. (2008) linkage-mapped the albino locus in American mink to two microsatellites known to be located in the region of the mink genome homologous to the TYR gene in other species. They also physically mapped a BAC clone containing one of the two linked microsatellites (Mvi6034) "to chromosome 7q1.1-q1.3 by fluorescent in situ hybridization".
Molecular basis: By sequencing the strong comparative positional (see Mapping section) and functional candidate gene (TYR), Anistoroaei et al. (2008) showed that albinism in American Mink is due to "a nonsense mutation in exon 1, which converts a TGT codon encoding cysteine to a TGA stop codon (c.138T>A, p.C46X; EU627590). The mutation truncates more than 90% of the normal gene product including the putative catalytic domains."
By sequencing a very strong comparative and functional candidate gene, Benkel et al (2009) showed that "marbled mink carry a mutation in exon 4 of the TYR gene (c.1835C > G) which results in an amino acid substitution (p.H420Q). The location of this substitution corresponds to the amino acid position that is also mutated in the TYR protein of the Himalayan mouse. Thus, the marbled variant is more aptly referred to as the Himalayan mink."
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|
|TYR||Neovison vison||7||NC_058097.1 (135398266..135284360)||TYR||Homologene, Ensembl , NCBI gene|
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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|
|332||Albinism||TYR||nonsense (stop-gain)||Naturally occurring variant||c.138T>A||p.(C46*)||2008||18822100|
|260||Himalayan||TYR||missense||Naturally occurring variant||c.1835C>G||p.(H420Q)||2009||19308642|
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.
|2009||Benkel, BF., Rouvinen-Watt, K., Farid, H., Anistoroaei, R. :|
|Molecular characterization of the Himalayan mink. Mamm Genome 20:256-9, 2009. Pubmed reference: 19308642. DOI: 10.1007/s00335-009-9177-6.|
|2008||Anistoroaei, R., Fredholm, M., Christensen, K., Leeb, T. :|
|Albinism in the American mink (Neovison vison) is associated with a tyrosinase nonsense mutation. Anim Genet 39:645-8, 2008. Pubmed reference: 18822100. DOI: 10.1111/j.1365-2052.2008.01788.x.|
- Created by Frank Nicholas on 09 Jul 2009
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