Wake Up The Cat

The colorpoint pattern is most commonly associated with Siamese cats, but may also appear in any domesticated cat. A colorpointed cat has dark colors on the face, ears, feet, and tail, with a lighter version of the same color on the rest of the body, and possibly some white. The exact name of the colorpoint pattern depends on the actual color, so there are seal points (dark brown), chocolate points (warm lighter brown), blue points (dark gray), lilac or frost points (silvery gray-pink), red or flame points (orange), and tortie (tortoiseshell mottling) points, among others. This pattern is the result of a temperature sensitive mutation in one of the enzymes in the metabolic pathway from tyrosine to pigment, such as melanin; thus, little or no pigment is produced except in the extremities or points where the skin is slightly cooler. For this reason, colorpointed cats tend to darken with age as bodily temperature drops; also, the fur over a significant injury may sometimes darken or lighten as a result of temperature change.
The tyrosine pathway also produces neurotransmitters, thus mutations in the early parts of that pathway may affect not only pigment, but also neurological development. This results in a higher frequency of cross-eyes among colorpointed cats, as well as the high frequency of cross-eyes in white tigers.