Black cats are a/a at ASIP. This type of black, which is recessive, also occurs in horses and in some herding breeds of dogs. Some cat books of sites also describe this a/a genotype as responsible for solid or self colored, but this is only true of the eumelanin solid colored cats - black, chocolate and blue.

The wild type of ASIP is presumed to be a mottled coloration, such as tabby stripes, since the domestic cat is thought to have evolved from a wild cat with a mottled appearance. A tabby is shown on the right. Some wild cats are a reddish color, probably similar to the lion's color or that of an Abyssian cat. The gene and allele that differentiates tabby (banded hairs) from Abyssian (banded hairs) patterns has not yet been identified.

The gene that causes eumelanin pigment to be brown instead of black is TYRP1, just like in dogs and several other mammals. This gene has been called the B locus. In cats there are two different mutations in TYRP1, leading to two shades of brown: chocolate and cinnamon. Cats that are homozygous for a premature stop codon, known as b1, are cinnamon which is a reddish brown. Cats that were homozygous b/b are typically called chocolate. Lyons et al. (2005 ) found that cats that are b/b1 would be closer in shade to chocolate.

Note that all solid chocolate or cinnamon cats are also a/a at ASIP because they produce only eumelanin pigment. In the cat fancy, solid is sometimes called self.

• Lyons LA, Foe IT, Rah HC, Grahn RA. (2005) Chocolate coated cats: TYRP1 mutations for brown color in domestic cats. Mamm Genome. 16(5):356-66
• Schmidt-Kuentzel A, Eizirik E, O'Brien SJ, 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(4):289-301

Just as in dogs, the gene causing black eumelanin pigment to be diluted to blue or grey is MLPH or melanophilin. A cat with this blue phenotype is typically said to be d/d in genotype. A cat with blue coat color is illustrated on the left by this stately Russian Blue. The same mutation was found in 26 cat breeds.

Ishida et al. (2006) suggest that this MLPH mutation causes black cats to be blue and orange cats to be cream. Likewise chocolate brown cats would be pale brown, often called lilac in cats. Cinnamon brown cats that are also d/d would be a very pale shade presumably.

• Ishida Y, David VA, Eizirik E, Schaeffer AA, Neelam BA, Roelke ME, Hannah SS, O'brien SJ, Menotti-Raymond M. 2006. A homozygous single-base deletion in MLPH causes the dilute coat color phenotype in the domestic cat. Genomics. 88(6):698-705.

The gene responsible for white cats with blue eyes - an albino phenotype is tyrosinase. The mutation in this gene is a premature stop codon. Albino cats usually are homozygous for this recessive mutation (i.e. they are c/c). Tyrosinase is an important gene in several pathways and therefore it is not surprising that such cats are usually deaf. The blue-eyed Angora at the left is likely deaf.

The wirehaired white cat on the right, is not an complete albino since one eye is pigmented. Cat fanciers call this "odd-eyed". What gene makes its coat white? This gene is sometimes called the W gene or locus, but has not yet been identified.

The gene responsible for colored points on a pale body has been found to be tyrosinase in most species studied. The assumption is that the mutation causes temperature sensitive expression of pigment on the cooler parts of the body - ears, muzzle, feet, tail tip and a pale color that looks almost white in some cases on the torso. This has typically been known as the Siamese pattern in cats and the allele is known as c^s. Cats homozygous for this mutation are have Siamese points. The pigmented points can be virtually any color.

Another mutation in Tyrosinase is responsible for the dark sepia brown color in some Burmese cats and the allele associated with this color is known as c^b. Cats homozygous for this mutation are solid dark sepia brown. For non-cat fanciers, what is confusing is that the Burmese breed of cats do not all have this classic Burmese color!

Cats that are compound heterozygotes, meaning one mutation of each type and therefore a genotype of c^s/c^b have an intermediate phenotype which is a brownish color with darker points visible either subtly or readily. The Tonkinese cat is noted for this pattern. Cats that are c^s/c^s have pale bodies with points that are markedly darker in color and readily visible.

All of the gene causing white spots or markings have not yet been identified in cats. Mittens, at the left, was my mother's last cat and is presumed to be a Domestic Shorthair. Although he has his paws all tucked under, you can guess by his name that he has white paws also. That type of white marking is very common in cats.

The mutation for white gloves in Birman cats only, has been identified in the KIT gene and is tested by VGL-UC Davis based on the research of Gandolfi et al.

Calico cats, such as the one on the left, produce areas of orange and black and also have white spotting. Such calico cats are females that are X^O/X^o. Cats that do not have white spotting but a genotype of X^O/X^o are tortoiseshell, such as the cat shown below. The cat on the right also has white markings but does not exhibit a calico pattern of distinct orange and distinct black patches. This cat has orange areas and tabby areas in a more intermingled arrangement. In the cat fancy, such as cat is sometimes called a "torbie", which is presumably a combined term from tortoiseshell and tabby.

Since normal males have only a single X chromosome, they can not exhibit calico or tortoiseshell patterns.