I do not have a Brindle just a bay, but I was wondering what gene or genes cause the Brindle color to happen. I have never seen a horse in real life with this just dogs (which I love). My bay does Brindle just a TAD in the sun during the summer, but nothing that stays. So does anyone have any idea what causes the Brindle color? Do any of you guys have a Brindle colored horse? If so post pictures!!