Dun dilute horse color

Dun is a dilution color. It is caused by the dun gene, D, diluting what would otherwise be a bay horse. It dilutes the reddish brown of the bay's body color to a yellowish color, and adds primitive markings or dun factors. These consist of a dorsal stripe and horizontal "zebra stripes" on the upper legs, and can also include a transverse stripe over the withers and markings on the ears.

A dun horse's genotype is A_E_D_, with E causing black color, A restricting it to the points, and D diluting the body color from red to yellow and adding dun factors.

D will also dilute otherwise black and chestnut horses, causing them to be grulla or red dun respectively. Those colors are featured below on this page. Regular dun, featured on this page, is is often called "zebra dun" to differentiate it from the other types of dun.

Red dun (D_ee) is a diluted form of chestnut. The body color of the red dun is a pale, washed-out yellowish red, and the point color is red, in various shades. Like all members of the dun family, primitive markings are present.

Like most colors, red dun comes in a variety of shades

Some chestnuts are so light that they are lighter than some shades of red dun. The difference, of course, is that the points of the red dun are darker than its body color, and the red dun, like all duns, has primitive markings

Grulla (pronounced "grew-yah," and also spelled grullo) is a slate or slate-brown color with black points and primitive markings (dorsal stripe, leg stripes, etc.). The horse also has a black face. Grulla is black diluted by the D gene, or aaD_E_. Unlike a grey or roan horse, the hairs of a grulla are all individually slate-colored. Greys and roans have colored hairs intermixed with white hairs.

Grulla comes in many shades, some light, some dark, some silvery, some olive-colored. All have black points, black masks, and primitive markings.