Population Genetics and Molecular Evolution of Higher Primate mtDNA

该项目的主要目标是确定mtDNA用于重建高等灵长类动物(猴子、猿和人类)的进化史的可靠性。利用线粒体DNA研究高等灵长类动物的进化依赖于三个关键假设：(1)我们知道两个物种的线粒体DNA彼此分化的速度；(2)这个速度随着时间的推移在不同的物种群体中是恒定的；(3)在一个物种中，个体的线粒体DNA大致相同。PI已经开始在一些亚洲猕猴物种上测试这些假设，并发现(1)同一物种成员之间的mtDNA差异很大，(2)mtDNA的差异率远远超过可接受的变化率，以及(3)不同种群或物种的差异率。这些发现表明，使用线粒体DNA重建进化关系和确定进化事件的日期存在严重问题。雌性猕猴从不离开它们出生的群体；结果可能与这种久坐不动的行为有关。因此，已经确定的问题在多大程度上将在类人猿和人类身上发现尚不清楚。国际猕猴协会建议将研究扩展到其他猕猴物种，并对亚洲叶猴进行类似的测试，这些亚洲叶猴的雌性猴子不一定留在原来的种群中。这项研究将首次对高等灵长类动物线粒体DNA进化的动力学进行全面评估。这些信息最终将有助于更好地了解人类及其近亲的进化史。

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.