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The molecular basis of a striped coat texture pattern that produces a brindle phenotype in a lineage of Quarter Horses has been identified by researchers in Switzerland. To avoid confusion with the spontaneous, not heritable brindle pattern associated with chimerism, the coat texture pattern has been named Brindle 1 (BR1). The stripes form a vertical pattern from the back to the sides of horses that is characterized by changes in hair structure as well as pigmentation. The hairs from the stripes are less straight and unrulier than hairs from the normally pigmented and textured coat. The BR1 phenotype is variable in that in some females, the predominant feature is the coat texture change while in others it can be the striped pigmentation. Males with BR1 mutation have sparse manes and tails but not the texture pattern. The BR1 phenotype can occur in any color background and shows seasonal changes (summer versus winter), with winter coat often having a “moth-eaten” appearance. The BR1 phenotype has an X-linked, semi-dominant mode of inheritance. Females with 1 copy of the BR1 mutation have the brindle phenotype. Females with 2 copies of the BR1 mutation (BR1/BR1) and BR1 males (only 1 X-chromosome present) have sparse manes and tails but not the striped coat texture pattern.