Dun Gene - Dun Mimics

Dun Mimics

Since the dun gene, when on a "bay dun" horse, can closely resemble buckskin, in that both colors feature a light-colored coat with a dark mane and tail, classic duns frequently are confused with buckskins. The difference between these two colors is the dun as a tan color, somewhat duller than the more cream or gold buckskin, and duns also possess primitive markings. Some buckskins do show countershading, but it is not related to the primitive markings of dun factor horses.

Genetically, a bay dun is a bay horse with the dun gene that causes the lighter coat color and the primitive markings. A buckskin is bay horse with the addition of the cream gene, causing the coat color to be diluted from red to gold, often without primitive markings.

A red dun may also be confused with a perlino, which is genetically a bay horse with two copies of the cream gene, which creates a horse with a cream-colored body but a reddish mane and tail. However, perlinos usually are significantly lighter than a red dun and generally have blue eyes.

To further confuse matters, it is possible for a horse to carry both dun and cream dilution genes; such horses with golden buckskin coloring and a complete set of primitive markings are referred to as a "buckskin dun" or a "dunskin". In the Fjord horse, duns that also carry the creme dilution are called uls dun or white dun (ulsblakk) and yellow dun (gulblakk) by their respective coat colors. On such horses, the light-shaded primitive markings are most noticeable during the summer months when the winter hair sheds.

Countershading is a usually a darker shade of the body color rather than the near-black of primitive markings on bay duns, but it may be harder to differentiate between countershading and a dorsal stripe on light-colored horses such as red duns. In such cases, pedigree analysis, DNA testing, studying possible offspring, and the presence of other primitive markings are used to determine whether a horse is a dun.