The primary goal of this project is to determine how reliably mtDNA can be used to reconstruct the evolutionary history of higher primates (monkeys, apes and humans). The use of mtDNA to study higher primate evolution rests on three critical assumptions: (1) that we know the rate at which the mtDNA of two species diverge from one another; (2) that this rate is constant over time and across different groups of species; and (3) that within a species, individuals have mtDNA that is more or less the same. The PI has begun to test these assumptions on a number of Asian macaque monkey species and has found (1) large mtDNA differences between members of the same species, (2) rates of mtDNA divergence that vastly exceed the accepted rate of change, and (3) divergence rates that vary among populations or species. These findings suggest serious problems with the use of mtDNA to reconstruct evolutionary relationships and date evolutionary events. Macaque monkey females never leave the group they are born in; the results may be related to this sedentary behavior. Therefore, the extent to which the problems already identified will be found in apes and humans is unclear. The PI proposes to investigate this by extending research to other macaque species and by performing similar sets of tests on the Asian leaf monkeys, whose females do not necessarily stay in their original group. This research will provide the first comprehensive assessment of the dynamics of mtDNA evolution in the higher primates. Such information will ultimately lead to a better understanding of the evolutionary history of humans and their closest relatives.
