Lineback Dun Definition and Primitive Markings

A major category of light colors that have primitive markings which are darker than the base color.

Primitive markings vary in extent and can occur in different combinations. The backstripe is the most consistent feature, and horses with colors of this group are called linebacked duns; the other types of "primitive" striping are much more variable. When primitive markings are present in an extreme degree, a horse can exhibit many stripes. The lineback stripe can also be seen on chesnuts and bays as they carry a dun factor in their pedigree. All of the variants of the zebra dun group have black points, although some of these fade slightly at the coronary band above the hoof.

Although primitive markings occur in primitive and undifferentiated breeds, they also occur in many highly developed non-primitve breeds of horses, such as Paso Finos. The markings by themselves in no way mean pimitiveness of breeding in a horse. The variability of the presence of these markings exist even in primitive breeds, such that not all the markings are always present.