CHEETAH

The cheetah has unusually low genetic variability and a very low sperm count and motility, and deformed flagella.^[7]Skin grafts between unrelated cheetahs illustrate this point in that there is no rejection of the donor skin. It is thought that the species went through a prolonged period of inbreeding following a genetic bottleneck during the last ice age. It probably evolved in Africa during the Miocene epoch (26 million to 7.5 million years ago), before migrating to Asia. New research by a team led by Warren Johnson and Stephen O'Brien of the Laboratory of Genomic Diversity (National Cancer Institute in Frederick, Maryland, United States) has recently placed the last common ancestor of all existing species as living in Asia 11 million years ago, which may lead to revision and refinement of existing ideas about cheetah evolution. Now-extinct species include: Acinonyx pardinensis (Pliocene epoch), much larger than the modern cheetah and found in Europe, India, and China; Acinonyx intermedius (mid-Pleistocene period), found over the same range. The extinct genus Miracinonyx was extremely cheetah-like, but recent DNA analysis has shown thatMiracinonyx inexpectatus, Miracinonyx studeri, and Miracinonyx trumani (early to late Pleistocene epoch), found in North America and called the "North American cheetah" are not true cheetahs, instead being close relatives to the cougar.^{[citation needed]}