USEFUL GENETIC TERMS

Abundism

Markings are more prolific than usual

Albinism

Lacking melanin, also known as amelanistic. "True" albinos entirely lack markings and have pale blue ("partial albino") or pink eyes ("true albino"), but there are many degrees of partial albino. Some forms of albino are temperature dependent e.g. the Siamese cat has a form of albinism where pigmentation develops on cooler areas of the body (the head, tail and legs) but is inhibited on the warmer parts of the body. Albinism can also occur in patches.

Anerythristic albinism

Lacking the red colour. The actual colour and pattern of the animal depends on what other colours are in the pattern. One effect might be a bluish-grey animal.

Axanthic albinism

Lacking the yellow colour. The actual colour and pattern of the animal depends on what other colours are in the pattern.

Chinchilla

The hair shaft lacks normal bands of pigment and may be pigmented only at the top. Known also as the "inhibitor" gene because it inhibits production of pigment. There is also believed to be a "wide band" gene because the hair shaft has a wide band of white.

Dilution

The colour is washed out e.g. black becomes blue (grey), red becomes cream, blue becomes lilac.

Erythrism

Black pigment is converted to red. The excessive amount of red pigment masks other colours.

Flavistic

Golden mutation. The overall effect is that of an pale animal photographed in sepia; all colours seem converted to shades of brown or golden-brown.

Golden

The hair-shaft has a wide band of gold. It is a combination of chinchilla or wide band and normal colouring.

Hypermelanistic

Having excessive black and/or brown pigment (usually just referred to as melanistic)..

Hypomelanistic

Having less black and/or brown colour than normal. These animals still have some pigment and may simply look "faded".

Leucistic

Similar to albino; white, but having dark eyes, some pigmented skin and often having "ghost markings" visible in certain light.

Maltesing

Another term for dilution of black into blue.

Melanism

Abnormal amounts of black pigment.

Mosaicism

Abnormal black patches of skin cells due to cell mutations in the embryo.

Nigrism

Black markings merge into black areas.

Partial Albinism

The correct definition is an albino with some residual pigmentation e.g. dark eyes, cream fur or ghost markings. However "partial albino" is also often used to describe animals with albino patches (piebald).

Piebald

Having white patches. Note: piebald is a normal colouration in some animals, this note only applies to animals which do not normally have black or white patches. In normally dark-coloured animals white patches may be due to albinism affecting certain areas of skin; in normally light-coloured animals, black/dark brown patches may be due to melanism. The patches are due to localised mutations in skin cells during embryo development. If the mutation occurs early in development, the patches are larger. If it occurs later, the patches are smaller.

Pseudomelanism

Combination of abundism and nigrism i.e. prolific markings coalesce to hid the background colour.

Rufism

Affects the depth of the red pigment turning it from yellow-orange into deep orange-red.

Schizochroism

One or more pigments are absent, altering the overall colour and pattern.

True Albino

Totally lacking in pigment - white fur and skin, no markings, blue or pink eyes.

Tyrosinase-negative Albino

An albino whose cells lack tyrosinase (an enzyme which synthesises melanin), usually producing a pale yellowish or cream animal with pink-eyes.

Tyrosinase Positive Albino

An albino not able to synthesise melanin, but able to synthesise tyrosinase, often resulting in a fawn or lavender (platinum) colour. Tyrosinase positive albinism ("partial albinism") is the most common form of albinism.

Xanthic

Having more yellow colour than normal.