Genes for the white coat: W-genes
W-genes: White coat, spots And socks
A cat with a black and white fur is probably one of the most common colors of normal domestic cats. A white coat color, spots or gloves are caused by the fact that the cells that produce pigment (melanocytes) are not distributed to the skin layer during embryonic development, which prevents a hair from being pigmented during growth. This disorder is caused by a defect in the so-called KIT genes. For dominant white (W), there are no pigment-producing cells present in the skin at all, so the coat cannot acquire color. This gene also causes blue eyes and deafness. For white cat with 2 blue eyes, 60-80% are completely deaf. In white cats with 1 blue eye, 30-40% are deaf and in white cats with other eye color, 10-20% are deaf, with the remaining portion often having impaired hearing in varying degrees.
In cats with partially white coats or white spots (Ws), pigment cells spread (only) to part of the skin. In those parts the coat can have its normal color (black, red, tabby etc). The rest is white. Partly white cats do not suffer from deafness. Cats without white fur is denoted by (w). Ws/Ws cats tend to have more white than Ws/W cats. The degree of white on the coat can vary greatly. The Turkish Van only has color on the ears and tail and the rest of the cat is completely white. This is called a Van pattern. Cats with only a few spots are called “harlequin.” Bicolor cats have a greater amount of (irregular) white spots. The pattern of cats that have a black face and a large spot on their back is called “cap and saddle.” When a larger part is black we call it “mask and mantle” and cats that have only a white chest and feet appear to wear a black suit and are therefore called “tuxedo” cats.
Finally, there are cats with only white gloves (wg), which is caused by another mutation. For Birman cats, this has even become part of the breed standard and all Birmans are wg/wg. The white glove mutation wg is fully recessive. The order of dominance of white is: W > Ws > w > wg.
- W/-: all-white cat.
- Ws/Ws: cat with white spots or mostly white.
- Ws/w: same as Ws/Ws, but often less white.
- Ws/wg: cat with white spots and white gloves.
- w/w: normal or non-white cat (apart from albino).
- w/wg or wg/wg: white gloved or mitted cat.
Incidentally, the white gloves in Ragdolls come from another dominant gene (designated Sb, Sm or s2). The effect of this gene are white feet, chin and a white strip on the underside of the body to the tail.