A Novel TYRP1 Mutation Associated with Brown Coat Color in Siberian Huskies
Brown coat color in dogs has previously been associated with mutations in the TYRP1 gene. The Tyrosinase Related Protein 1 encoded by this gene plays a key role in the biochemical pathway in which pigments are synthesized in skin melanocytes. Defects in the TYRP1 protein subsequently cause a change in the production of black eumelanin pigment, which results in a brown coat color instead of black. The known TYRP1 variants, in what is called the B-locus, are routinely tested for in dog genetic health and coat color panels, which aids dog breeders in evaluating their dogs and making breeding decisions going forward. Here, we investigated a family of Siberian Husky and Husky-mixes whose brown coat color could not be explained by previously known b-variants alone, and report a sixth TYRP1 b-variant which we have named “bh”. The Siberian Husky and Husky-mixes in which the bh allele contributed to the brown phenotype were compound heterozygotes with at least one other known b allele, while all non-brown dogs had one or two B (wild-type) alleles. This is consistent with a recessive mode of inheritance, as also seen with other b-variants. These results add to our understanding of genetic mechanisms leading to coat color variation in dogs and other mammals.