grey (born red dun)
gris (né alezan dun)
Description
Progressive coat: the horse is born a base color (noted in parentheses), then gradually greys throughout its life until it becomes white or very light grey. This process can take anywhere from a few years to over a decade.
Visual traits
Born colored · Progressive greying · White or grey at maturity · Increased melanoma risk
Genetic basis
Grey G/- — the STX17 gene causes progressive, irreversible hair depigmentation.
The Dun gene dilutes the base coat and adds primitive wild-horse markings: a dorsal stripe along the spine, leg barring, and sometimes shoulder stripes.
The Grey gene causes progressive greying: the horse is born colored (base coat noted) and becomes grey-white with age. The base coat is only visible at birth or in very young foals.