Dilutions Overview
Every horse has an underlying base color of Black, Bay, or Chestnut. However, certain genes can modify the appearance of these colors by reducing or altering the pigmentation in the horse's coat. These are dilution genes.
Different dilutions affect the pigmentation of a horse's coat in different ways. Some primarily lighten red pigment, while others affect black pigment. Some may even impact both.
Depending on the dilution, these changes may affect the body, mane, tail, legs, and sometimes even the horse's skin and eye color.
How Dilutions Affect Base Colors
Just because a horse has a dilution doesn't mean that all horses with that dilution will look the same.
For example, a chestnut horse that inherits one copy of the Cream dilution (CR/n) becomes Palomino, while a bay horse with the same dilution becomes Buckskin.
Both horses have the same dilution but appear visually different due to their different base colors.
Dilutions do not replace a horse's base color. They modify its appearance, meaning a horse that looks cream, gold, silver, etc., still has an underlying genetic base color that it can pass down to its offspring.
Dominant & Recessive Dilutions
Like other genetic traits, dilution genes can be dominant or recessive.
Some only require one copy to visibly affect the horse's coat, while others require two copies. Certain dilutions also produce different appearances depending on whether the horse is homozygous or heterozygous.
Some dilutions are only visible on certain base colors.
For example, a horse carrying the Silver gene (Z/n or Z/Z) will not visibly display the dilution on a chestnut (e/e) coat because Silver affects black pigment.
However, this horse could still produce Silver offspring, as it can pass down the gene through breeding.
Combining Multiple Dilutions
It's also possible for a horse to inherit multiple dilution genes, which can interact with each other to produce additional coat color combinations.