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）进化史的可靠性。利用mtDNA来研究高等灵长类动物的进化取决于三个关键假设：(1)我们知道两个物种的mtDNA彼此分化的速率；(2)这一速率随时间和不同物种群是恒定的；(3)同一物种内，个体的mtDNA或多或少是相同的。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分化率远远超过公认的变化率，(3)种群或物种之间的分化率不同。这些发现表明，使用mtDNA来重建进化关系和确定进化事件的日期存在严重问题。猕猴雌性永远不会离开它们出生的群体；结果可能与这种久坐行为有关。因此，目前还不清楚已经确定的问题在猿类和人类身上会有多大程度的影响。PI建议通过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来调查这一点，亚洲叶猴的雌性不一定留在原来的群体中。这项研究将首次全面评估高等灵长类动物mtDNA进化的动态。这些信息最终将有助于更好地理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.