C-locus colourpoint / Siam / Mink / Burmese (TYR-related) - Cat

C-locus colourpoint, Siam, Mink and Burmese

This genetic test examines two TYR alleles at the C locus: c.679G>T for Burmese/sepia and c.940G>A for Siamese colourpoint. Together these alleles explain C-locus variants such as colourpoint, Siam, Mink, Burmese and sepia.

What does this mean for coat colour?

TYR variants can make tyrosinase temperature-sensitive. This often creates darker pigment on cooler body areas such as ears, paws, tail and muzzle. Two Siamese alleles give a stronger colourpoint pattern; two Burmese alleles give sepia/Burmese; one Siamese and one Burmese allele usually give mink, an intermediate form.

Why this test is useful

• The test clarifies C-locus combinations for Siamese, Burmese and Mink.
• Breeders can plan colour expectations and carrier status more accurately.
• The result helps combine colour phenotypes correctly with other loci such as B, D and E.

The alleles act as an allele series: final colour depends on the combination of both TYR alleles and other coat-colour genes.