Bay and Brown are actually a modification of Black. In other words, bays and browns are black horses with a dominant modifying gene called AGOUTI added.
There are six basic color patterns in the Appaloosa horse, and endless variations. Appaloosas are best known for their spots, but they have many variations in coat colors. The appy is a very versatile breed that has many desirable qualities.
A pintaloosa is a color breed that is the combination of Appaloosa and Pinto spotting patterns on the same horse. This combination is rare, but does occur from time to time on Mustangs, and occasionally in domestic horses. They can be registered with the International Pattern Spot Horse Registry (IPSHR) .