Cat coat genetics

Cat coat genetics determine the coloration, pattern, length, and texture of feline fur.

For example, a Neva Masquerade (Siberian colorpoint) could wear point coloration, the stereotypical coat of a Siamese.

The browning gene B/b/bl codes for TYRP1 (Q4VNX8), an enzyme involved in the metabolic pathway for eumelanin pigment production.

), and Oo results in a tortoiseshell cat, in which some parts of the fur are orange and other areas non-orange.

"Solid" red show cats are usually low contrast ticked tabbies.

[5] Tabby cats have a range of variegated and blotched coats, consisting of a dark pattern on a lighter background.

[citation needed] However, the following different coat patterns are all possible:[citation needed] The agouti factor determines the "background" of the tabby coat, which consists of hairs that are banded with dark eumelanin and lighter phaeomelanin along the length of the hair shaft.

The wild-type dominant A causes the banding and thus an overall lightening effect on the hair, while the recessive non-agouti or "hypermelanistic" allele a does not initiate this shift in the pigmentation pathway.

As a result, homozygous aa have pigment production throughout the entire growth cycle of the hair and therefore along its full length.

[13] These homozygotes are solidly dark throughout, which obscures the appearance of the characteristic dark tabby markings—sometimes a suggestion of the underlying pattern, called "ghost striping", can be seen, especially in bright slanted light on kittens and on the legs, tail and sometimes elsewhere on adults.

A major exception to the solid masking of the tabby pattern exists, as the O allele of the O/o locus is epistatic over the aa genotype.

That is, in red or cream colored cats, tabby marking is displayed regardless of the genotype at the agouti locus.

However, some red and most cream tabbies do have a fainter pattern when lacking an agouti allele, indicating that the aa genotype does still have a faint effect even if it does not induce complete masking.

[citation needed] A threonine to asparagine substitution at residue 139 (T139N) in this protein is responsible for producing the tabby phenotype in domestic cats.

[15] The wild-type (in African wildcats) is the mackerel tabby (stripes look like thin fishbones and may break up into bars or spots).

Ticked tabbies are rare in the random-bred population, but fixed in certain breeds such as the Abyssinian and Singapura.

[20] Male tortoiseshells can occur as a result of chromosomal abnormalities such as Klinefelter syndrome, by mosaicism, or by a phenomenon known as chimerism, where two early stage embryos are merged into a single kitten.

An Oo cat with a large amount of white will have bigger, clearly defined patches of black/red and blue/cream, and is called a calico in the US.

Blue tortoiseshell, or diluted calico, cats have a lighter coloration (blue/cream) and are sometimes called calimanco or clouded tiger.

The shades which are present in the pale bands of a tabby are not considered to constitute a separate color.

On solid cats, it turns the base of the hair pale, making them silver smoke.

However, there is no golden smoke, because the combination of wide band and nonagouti simply produces a solid cat.

[38][unreliable source][39] The genetics involved in producing the ideal tabby, tipped [fr], shaded, or smoke cat is complex.

For example, the silver melanin inhibitor gene in some instances does not block pigment, resulting in a grayer undercoat, or in tarnishing (yellowish or rusty fur).

Likewise, poorly-expressed non-agouti or over-expression of melanin inhibitor will cause a pale, washed out black smoke.

The length, density and proportions of these three hairs varies greatly between breeds, and in some cats only one or two types are found.

[43][44] Double-coated cats with thick undercoats require daily grooming as these coats are more prone to matting.

[43] Double coats are found in for example the Persian, British Shorthair, Maine Coon and Norwegian Forest cat.

Siberians and Neva Masquerades are known for their unique triple coats,[43] which provides double insulation to withstand their natural cold climate.

Rexes appeared in America, Germany and the UK, where one breeder caused consternation by calling them "Maine Waves".