Cat Coat color – C locus (Color/Burmese, Siamese, Albino)
The C locus contains the c gene or its mutatations. In many animal species it is called albino. Others refer to it at the chinchilla gene or the concentration gene. The coat color loci influence the development, maturation, and migration of melanocytes as well as the synthesis of melanin and the formation, transport, and transfer of melanosomes. A change in number of mature melanocytes located in the hair follicles or a change in the composition of their pigment-loaded melanosomes will affect the color of the growing hair shaft.
The Siamese cat has a highly recognized coat colour phenotype that expresses pigment at the extremities of the body, such as the ears, tail and paws. This temperature-sensitive colouration causes a mask on the face and the phenotype is commonly referred to as pointed. Burmese is an allelic variant that is less temperature-sensitive, producing more pigment throughout the torso than Siamese. Albinism is a congenital disorder that is characterized by lack of pigment in hair, skin and eyes. Recently, the causative mutations for the siamese and burmese temperature sensitive alleles, and complete albinism have been identified in tyrosinase (TYR). Allelic series at the colour C locus is: C (full colour) > cb (burmese) ≥ cs (siamese) > c (complete albino).
Schmidt-Küntzel, A., Eizirik, E., O’Brien, S.J., and Menotti-Raymond, M. (2005). Tyrosinase and tyrosinase related protein 1 alleles specify domestic cat coat color phenotypes of the albino and brown loci. J. Hered. 96, 289–301.