#16 The Champagne gene - A unique colour dilution

Another in the colour genetics series

The Champagne gene is a dominant dilution gene that affects both red and black pigments in a horse's coat. Its presence results in distinctive coat colors, skin, and eye characteristics.

The Champagne gene is dominant, meaning that only one copy of the gene (Ch) is necessary for the Champagne traits to be expressed. The possible genotypes are:

• Ch/Ch (Homozygous Champagne): The horse will display Champagne characteristics and will pass the gene to all offspring.

• Ch/n (Heterozygous Champagne): The horse will display Champagne characteristics and has a 50% chance of passing the gene to offspring.

• n/n (Non-Champagne): The horse does not carry the Champagne gene and will not display or pass on Champagne traits.

The champagne gene is associated with mutation (slc36a1) resulting in an amino acid change that affects pigment production in both skin and coat.

This single mutation affects both red and black pigments, which is why it dilutes all base coat colors and creates that distinct freckled skin and light eye combination.

Unlike some other dilution genes, Champagne horses exhibit:

• Skin: Pinkish skin that develops abundant dark freckles as the horse matures.

• Eyes: Foals are born with bright blue eyes, which typically darken to hazel, amber, or green in adulthood.

• Coat: A diluted coat color that varies depending on the horse's base color. Typically with striking iridescence.

These traits make Champagne horses stand out, and they are often mistaken for other diluted colors like palomino or buckskin. However, the freckled pinkish skin and unique eye color are telltale signs of the Champagne gene.

Champagne color variants: