There are plenty of white areas in the color genetics of horses, considering all of the combinations of color-altering genes horses come in almost every color imaginable.Sooty is a common color modifier that can act on both red and black based coats. Sooty, also known as smutty or countershading, causes dark hairs to be spread throughout a horses coat, usually concentrated from the top of the back down. Sooty horses often have spectacular dappling because of the contrast of colors in their coats. Sometimes the sooty hairs are concentrated into lines resembling leg barring and dorsal stripes on non-dun horses. Some horses are so sooty that their true color is unrecognizable.