OVERVIEW

The cream gene is a dilution gene expressed in horses, and produces lighter colours. When one copy of the gene is present, it dilutes "red" color (chestnut) to yellow or gold, and red manes to white, but does not dilute black colour at all. When two copies of the gene are present, both red and black hairs become a paler color; red hairs still become cream, and black hairs become reddish.

Cream horses are not "white" horses. Dilution colouring is not related to frame overcoat patterns or lethal white syndrome, nor is cream related to the controversial "white" or "dominant white" (W) gene; it does not produce white horses.

Colors produced by the cream gene - the cream gene produces the colours:

cremello
perlino
palomino
buckskin
smoky black and smoky cream

What it does
The cream gene is an "incomplete dominant" gene, which means that it is expressed to some degree even when there is only one copy of the gene-it is dominant-but it expresses itself even more when there are two copies (one from each parent).

Coat color: The cream gene lightens the base coat. One copy lightens red (chestnut) colouring to pale yellow or gold, such as palomino, but does not overtly affect black color. Two copies will lighten both red and black hairs.

Eye colour: double dilutes have blue eyes (unlike brown eyes of a grey and some white horses). Depending on the genes carried by the other parent, a single dilute, such as a Palomino, can be born with bluish brown eyes and pinkish skin that darkens after birth, or may be born with dark eyes and skin.

Single dilutes
Single dilutes receive the cream dilution gene from only one parent. The other parent does not carry the dilution gene.

Palomino: One parent genetically contributes the cream gene, and both parents contribute a "red" base coat gene. The cream gene lightens the coat to pale yellow/ gold and the mane to white, producing a palomino.

Buckskin: One parent genetically contributes the cream gene, and one or both passes on the genes for bay (the black base gene and the agouti gene that restricts the black to the points only. The single copy of the cream gene lightens the coat to pale yellow, but cannot change black, leaving the mane, tail, and lower legs black.

Smoky black: A single copy of the dilution gene is added to the gene for a black base colour. One cream gene cannot change the color of black hairs, so the horse looks black, "masking" the cream gene. Although the gene is masked, it can be passed on. Thus a smoky black may sometimes produce, for example, a buckskin or palomino horse when crossed on a bay or chestnut, even though neither parent appears to have the gene. Smoky black only occurs to genetically black horses. Bays and chestnuts, no matter how dark their base coat, will have red hairs diluted to gold.

Double dilutes
Double dilutes have 2 cream genes (one from each parent). This even further lightens the red colour: from the golden color of one dilute to a pale cream color of the double dilute. It also results in lightening of black hairs to a reddish color.

Double dilutes are not true white horses, nor are they albinos, even though they have pink skin. There are no true albinos in the horse world.

Nor are double-dilutes grey: they have blue eyes and pink skin, whereas a grey horse has dark eyes and black skin.

Cremello: The double dilution of chestnut/red coats. The body and mane is a cream colour (hence the "cream gene").

Perlino: Double dilution of bay, so that the body is a light cream, with reddish points (mane, tail, lower legs).

Cremello and Perlino horses sometimes fade in color as they mature, so that they look almost white. Their eyes and skin remain unchanged.

Smoky cream: Double dilution on a black coat. The cream gene is not completely hidden as it is in the smoky black. The horse becomes a light gold or cream color which can be difficult to tell from a cremello or perlino (although colors vary). If one wants to be sure of the base color, the horse can be tested for the presence of the Agouti and Extension genes.

Color differences

Other dilution genes in horses
There are three other dilution genes in horses, each producing different effects than does cream:

Dun color is produced by a separate dun gene that acts upon a base coat colour to produce a different form of colour dilution, along with distinctive "primitive" markings that include a dorsal stripe, horizontal leg striping, and usually a duller shade of dilution than cream; classic duns are more tan than gold. It is also a simple dominant, not an incomplete dominant.

The Champagne gene produces a dilution that strongly resembles cream. However horses with Champagne are born a different colour than they mature, usually have amber or green eyes in adulthood and usually have mottled skin.

The Silver dapple dilution acts only on a black coat, lightening the body coat to a chocolate brown and the mane to a lighter shade of flaxen or silver. It can be carried by non-black horses, but will not manifest absent black colouring. It has no impact on skin colour or eye shade.

Other terminology
This dilution gene is sometimes also called the "creme" gene. However the spelling most often used by geneticists, is "cream." "Creme" is actually an abbreviated form of "cremello", which refers specifically two cream genes on a chestnut base.