The cross between a Gray Black stallion, whose coat the (G) gene acts on the base coat promoting progressive lightening throughout the horse's life until reaching very pale or completely white tones. Entirely black coat, with no dilutions and no Agouti gene action restricting black pigment to the points., and a Grullo mare with coat the Dun gene acts on the base color, adding the characteristic dark dorsal stripe. In some cases it lightens the body tone and may also produce zebra-like leg markings. Entirely black coat, with no dilutions and no Agouti gene action restricting black pigment to the points., can produce 8 different coat colors: Gray Dun Black (22%), Grullo (22%), Gray Black (22%), Black (22%), Gray Dun Chestnut (3%), Dun Chestnut (3%), Gray Chestnut (3%) and Chestnut (3%). Results vary according to the genotype of each parent — use the filters above to explore specific combinations.