Coat Colour C-Locus (Siamese)

Coat colour in cats is controlled by a wide range of different genes working together. These genes are often referred to as “loci”. The C-Locus, a.k.a. Colour Locus, corresponds to the gene for tyrosinase (TYR). Recessive mutations to TYR can cause various degrees of Type 1 Oculocutaneous Albinism (OCA1), a failure to produce pigment, which leads to a silvery-white coat and light-coloured eyes. This can range between the distinctive point colouration of the Siamese cat, to full albinism.

The mutation analysed in this test, designated as “cs”, is responsible for Siamese-type point colouration. It is recessive to the normal genotype (“C”), but dominant over most other C-Locus mutations. A cat that carries one cs and one cb allele will display a mink coat instead.