The cross between a Grullo stallion, whose 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., and a Dun Dark Brown 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. Dark brown coat, often nearly black, with black points, expressed over the bay base., can produce 8 different coat colors: Dun Bay (40%), Grullo (21%), Bay (13%), Dun Chestnut (9%), Black (7%), Dun Dark Brown (4%), Chestnut (3%) and Dark Brown (1%). Results vary according to the genotype of each parent — use the filters above to explore specific combinations.