This project will examine the dynamics of mtDNA (mitochondrial DNA) dispersal within specific macaque populations; estimate levels of mtDNA diversity within and among populations of macaque species that have mainland and island distributions; and, test the hypothesis of rate constancy by examining levels of divergence among macaque populations. Molecular study of macaques is important because of several similarities with humans. (1) Macaques are thought to have radiated at about the same time as the emergence of the genus Homo. (2) Their spread in Southeast Asia parallels the expansion of hominids into the same part of the world. (3) Macaques and humans share many demographic attributes relevant to genetic change. For these reasons, demonstration of a relationship between the zoogeography of the macaques and the rate of molecular change implies that key events in our own past history can be similarly dated.