Evolution of mitochondrial DNA in monkeys, apes, and humans

The size of the primate single mitochondrial DNA molecular ring, the genetic technology for obtaining pure samples, the use of nucleotide sequence and restriction endonuclease analyses, and the relatively rapid rate of evolution make mtDNA variation useful for microevolutionary studies within and between species despite the informational content of the 37 genes being restricted to one locus because of complete linkage. The data on chimpanzees, gorillas, orangutans, and gibbons support the hypothesis that the two African apes are the closest living biological relatives of humans and favor a closer relation of chimpanzees and humans than of gorillas and humans. The data support the origin of Homo sapiens by regional phyletic transition from H. erectus, starting in Africa in the Middle Pleistocene, and oppose the hypothesis of rapid world-wide replacement by migration from a single source. The human continental races share a majority of both their mitochondrial and nuclear gene pools.