Identification of mutant gene for Black crystal coat and non-allelic gene interactions in Neogale vison.

Sable (Martes zibellina) and American mink (Neogale vison) are valuable species characterized by a variety of coat colour produced on fur farms. Black crystal fur phenotype is Mendelian codominant trait: heterozygous animals (Cr/ +) have white guard hairs scattered predominantly on the spine and the head, while homozygous (Cr/Cr) minks have coats resembling the Himalayan (ch/ch) or white Hedlund (h/h) types. It is one of the most recent of more than 35 currently known phenotypic traits of fur colour in American mink. Black crystal fur phenotype was first described in 1984 in the Russian population of mink, which had undergone selection for domestic defensive response to humans. Here, we performed whole-genome sequencing of American mink with Cr/Cr phenotype. We identified a missense mutation in the gene encoding the α-COP subunit of the COPI complex (COPA). The COPI complex mediates retrograde trafficking from the Golgi system to the endoplasmic reticulum and sorting of transmembrane proteins. We observed an interaction between a newly identified mutation in the COPA gene and a mutation in the microphthalmia-associated transcription factor (MITF), the latter mutation led to the formation of the white Hedlund (h/h) phenotype. Double heterozygotes for these mutations have an entirely white coat and a black-eyed phenotype similar to the phenotype of Cr/Cr or h/h minks. Our data could be useful for tracking economically valuable fur traits in mink breeding programs to contribute to global fur production.

Shadow coat colour in American mink associated with a missense mutation in the KIT gene.

The classical genetic analysis describes more 35 mutations that are involved in the formation of the American mink (Neovison vison) fur colour phenotype. To date, only eight of these mutations have been linked to specific genes. Shadow is a member of the commercially valuable Black cross colour family. Here, we performed whole-genome sequencing of the American mink with a Shadow Silverblue (Sh /+ p/p) phenotype. We identified a missense mutation (c.2374 G>T) in the gene encoding the KIT proto-oncogene, receptor tyrosine kinase gene (KIT), which plays a critical role in melanogenesis as well as in the survival, growth and development of other cell types. The reported mutation results in amino acid substitution p.Asp792Tyr in a highly conserved catalytic loop of the KIT protein.

Genome analysis of American minks reveals link of mutations in Ras-related protein-38 gene to Moyle brown coat phenotype.

Over 35 fur colours have been described in American mink (Neovison vison), only six of which have been previously linked to specific genes. Moyle fur colour belongs to a wide group of brownish colours that are highly similar to each other, which complicates selection and breeding procedures. We performed whole genome sequencing for two American minks with Moyle (m/m) and Violet (a/a m/m /p/p) phenotypes. We identified two frame-shift mutations in the gene encoding Ras-related protein-38 (RAB38), which regulates the trafficking of tyrosinase-containing vesicles to maturing melanosomes. The results highlight the role of RAB38 in the biogenesis of melanosomes and melanin and the genetic mechanism contributing to hair colour variety and intensity. These data are also useful for tracking economically valuable fur traits in mink breeding programmes.