Morgan - The first documented American breed, the Morgan horse owes its lineage to the original stud Justin Morgan. The Morgan blood has been a contributor to other North American breeds like the Saddlebred, Standardbred and the Tennessee Walking horse.
horse chimera:the bonding of fraternal twins in utero gives rise to unusual striping and brindle horses. DNA testing of a chimera will result in two completely different dna genes, and can even be different genders. It's literally two horses in one body.