From Wikipedia:
A piebald horse, Tobiano pattern A piebald or pied animal is one that has a pattern of unpigmented spots (white) on a pigmented background of hair, feathers or scales. Thus a piebald black and white dog is a black dog with white spots. The animal's skin under the white background is not pigmented.
Location of the unpigmented spots is dependent on the migration of melanoblasts (primordial pigment cells) from the neural crest to paired bilateral locations in the skin of the early embryo. The resulting pattern appears symmetrical only if melanoblasts migrate to both locations of a pair and proliferate to the same degree in both locations. The appearance of symmetry can be obliterated if the proliferation of the melanocytes (pigment cells) within the developing spots is so great that the sizes of the spots increase to the point that some of the spots merge, leaving only small areas of the white background among the spots and at the tips of the extremities.
Animals with this pattern may include birds, cats, cattle, dogs, foxes, horses, cetaceans, deer, pigs, and snakes. Some animals also exhibit colouration of the irises of the eye that match the surrounding skin (blue eyes for pink skin, brown for dark). The underlying genetic cause is related to a condition known as leucism.
I hope that helps . .it sure was helpful to me.
Lastly, a special thanks to Dyna for pointing me in this direction. You rock!
~ Rick
