The Champagne dilution gene lightens a horse's coat color by diluting the original pigment. The specific color produced will depend on the horse's base color — black coats can lighten to a dark brown, chestnut coats to an apricot or gold, and bay coats to a golden brown. A horse can also carry more than one dilution gene, which can further affect coat color.
Although similar to the cream, pearl and dun dilutions, the champagne gene has certain characteristics that distinguish it from other dilutions. Common characteristics of a champagne horse include pinkish freckled or mottled skin, a shiny coat that is often slightly darker in the winter, and a hazel eye color. Champagne horses are typically born with blue eyes that evolve to a hazel or an amber color. They also have pink skin that becomes darker and more freckled over time, especially around the eyes and muzzle. The champagne coloration has been documented in quarter horses, Tennessee Walkers, American Saddlebreds, Missouri Fox Trotters, Miniature Horses and several other breeds.
Base Color Interaction of Champagne Dilution:
Uniform black horses (excluding bay) are diluted to a classic champagne color. This involves the lightening of all body pigmentation to a pale-black color.
Chestnut/sorrel-based horses are diluted to a gold color. Full coat modification occurs, leading to uniform dilution of the body. Additionally, the gold horse will often have a flaxen mane and tail. Gold champagne horses are visually similar to chestnut-based horses modified by the cream gene (Palominos).
Bay horses carrying the champagne dilution are designated as amber. Unlike coat dilutions that only work upon black pigment, the champagne gene will dilute the whole coat of the bay horse. Amber champagnes are sometimes referred to as amber buckskins.
The champagne dilution is caused by a dominant gene, meaning that a horse with a single copy of the champagne gene will have champagne characteristics. Unlike cream dilution, there are no visual differences between a horse with one copy or two copies of champagne. A homozygous champagne horse (Ch/Ch) will always pass one copy of the champagne gene to its foal. Heterozygous horses (n/Ch) have a 50% chance of passing the gene on to its foals.
Animal Genetics offers testing for the dominant champagne gene mutation. DNA testing may be useful in cases where a horse has previously tested negative for cream or silver dilutions, but appears to have a lightened coat. Testing is also used to determine whether or not a horse has two copies of the champagne gene and will pass a copy onto offspring.
|Homozygous: Horse has two copies of the Champagne Dilution gene and will appear Champagne. Horse will pass this gene on to all offspring.
|Heterozygous: Horse has one copy of the Champagne Dilution gene and will appear Champagne. Horse has a chance to pass this gene on to any offspring.
|Negative: Horse is negative for the Champagne Dilution.
Champagne coat color in horses is controlled by a single, autosomal-dominant gene (CH). The phenotype produced by this gene is valued by many horse breeders, but can be difficult to distinguish from the effect produced by the Cream coat color dilution gene (CR). [PubMed: 18802473]