Primitive markings

[2] All dun horses possess at least the dorsal stripe,[1][2][3] but the presence of the other primitive markings varies.

[1][4] Primitive markings in horses are an example of atavism: preservation of or reversion to ancestral type.

In Przewalski's horse, the dorsal stripe is usually dark brown, while it is black in the bred-back tarpan.

Dorsal stripes on dun horses with the cream gene seem unaffected by cream: smoky black-duns ("smoky grullas"), buckskin-duns ("dunskins"), and palomino-duns ("dunalinos") have black, brown, or red dorsal stripes, as well.

[1] Leg bars are most commonly seen on or above the knees and hocks, and reflect the underlying coat color.

[7] Leg bars are prominent on Grevy's zebras and mountain zebras, and African wild asses also have well-defined black leg bars below the forearm and gaskin on a white or pale background.

[1] One classical genetics study concluded that stripes on the front legs seem to follow an autosomal dominant mode of inheritance.

It is more marked in breeds closest to the wild African ancestors of the domestic donkey.

[9] Indistinct or poorly defined markings in these regions are often called neck or shoulder smudges, patches, or shadows.

[7] Such characteristics are very visible among the Fjord horses, which have their sandwich-patterned manes shaved short and upright.

[4] Primitive markings on non-duns can be seasonal, visible only when the horse is shedding its coat.