The Cream Gene is a modifier, or a gene that acts on one of three base colours in horses.  The three base colour are chestnut, bay, and black. Some people classify brown as separate colour but for the purposes of this discussion, we will group brown with black since the inheritance is the same.

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The Cream Dilution can either be expressed as a single dilution, or a double dilution. Every chromosome has two alleles that represent the way in which each chromosome is inherited and you receive one allele from each parent. Simply put, the chromosomes (usually represented by letters) appear in pairs. To review high school biology, these pairs are generally dominant or recessive. Dominant genes are represented by two capital letters or one capital and one lower-case. The animal appears the same (phenotype) whether they are EE or Ee. The recessive form is represented by two lower-case letters ee.

The cream gene in the single form acts upon chestnut, bay and black by diluting the red colour to cream. The Cream Colour may be light enough to appear almost white to a dark chocolate tan colour. The black is generally unaffected so bay horses horses retain the black points, and mane/tail. Black horses appear somewhat diluted- a mousey chocolate. Horses with a single Cream dilution generally have dark eyes (unless blue from paint patterns) and black skin except where there are white markings (paint markings, facial markings, and leg markings).

The double dilution, or two Cream Genes acts upon both the red and black colours. The red become light cream/off white, and the black lightens to cream. In a bay horse with two cream genes, the body colour is light cream and the points appear as a darker shade of cream. Smokey Black Creams have a slightly over all darker shade but without genetic testing, it is impossible to determine what the base colour is in these horses. All double dilute Cream horses all have pink skin and blue or light green/hazel eyes.

The double dilute horses (Cremello, Perlino & Smokey Cream) are difficult to distinguish by appearance or phenotype alone. It is possible the double dilutes are all cremellos, or perlinos- or they are dirty. Google Perlino, Cremello, or Smokey Cream to see how they truly look- they are stunning colours.

The “Sooty” modifier is a additional genetic trait in which the horse’s coat looks like someone airbrushed darker colouration over the coat. In some extreme cases, the sooty modifier can turn a palomino so dark it appears ‘chocolate’ coloured- as in the case of Cloud’s son Bolder (photos below). Sooty can occur in any color and is believed to help break-up the outline/contour of a horse (countershading) and making it harder for predators to estimate the distances of the their prey.

Cream dilutions can also appear with other dilutes such as Dun. The resulting horses are called Dunalinos (dun + palomino) and Dunskins (dun + buckskin). It can be a challenge to tell pale palominos from cremellos/perlinos horses, but look at the muzzle and other mucous membranes (grey in Palomino, pink in creams). Watch for facial markings which also appear pale-pink even on palominos. The eyes are usually dark in Palominos, and pale green or blue in Creams.

BASE	ONE CREAM GENE	TWO CREAM GENES
BAY	BUCKSKIN	PERLINO
CHESTNUT	PALOMINO	CREMELLO
BLACK	SMOKEY BLACK	SMOKEY CREAM

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Chestnuts

 

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BAYS

                 

 

Genotype at the agouti locus	Chestnut horses	Palomino horses
A+_	Light chestnut	Cream palomino
AA_	Red chestnut, with AAAA being the reddest	Golden palomino
At_	Standard chestnut	Seasonal palomino
Aa Aa	Liver chestnut	Chocolate palomino

 Bibliography
Gower, J. (1999). Horse color explained: A breeder’s perspective. North Pomfret, VT: Trafalgar Square.    

Kathman, L. (2014). The equine tapestry: An introduction to horse colors and patterns. Charlotte, NC.: Blackberry Lane Press.  

Sponenberg, D. P. (1996). Equine color genetics. Ames: Iowa State University Press.

Presented by Dr Meredith Hudes-Lowder