Mouflon scientific literature as separate species, "Ovis musimon" and "Ovis orientalis". The mouflons are also sometimes treated as a subspecies of the domestic sheep, "Ovis aries", named with the same subspecific epithet as above: "O. a. musimon", "O. a. ophion", etc. Based on comparison of mitochondrial cytochrome b gene sequences, three groups of sheep ("Ovis") have been identified: Pachyceriforms of Siberia (snow sheep) and North America (bighorn and Dall sheep), Argaliforms (argali) of Central Asia, and Moufloniforms (urial, mouflon, and domestic sheep) of Eurasia. However, a comparison of the mitochondrial DNA control region (CR) found that two subspecies of urial, "Ovis
Wild horse stock from which domesticated horses are descended. The horse family Equidae and the genus "Equus" evolved in North America, before the species moved into the Eastern Hemisphere. Studies using ancient DNA, as well as DNA of recent individuals, show the presence of two closely related horse species in North America, the wild horse and "Haringtonhippus francisci", the "New World stilt-legged horse"; the latter has been taxonomically assigned to various names. Currently, three subspecies that lived during recorded human history are recognized. One subspecies is the widespread domestic horse ("Equus ferus caballus"), as well as two wild subspecies: the recently extinct