Department of Biology, McMaster University, Life Sciences Building, Hamilton, Ontario L8S 4K1, Canada.
Genetics. 2010 Jul;185(3):923-37. doi: 10.1534/genetics.110.116228. Epub 2010 Apr 20.
Sex-specific differences in dispersal, survival, reproductive success, and natural selection differentially affect the effective population size (N(e)) of genomic regions with different modes of inheritance such as sex chromosomes and mitochondrial DNA. In papionin monkeys (macaques, baboons, geladas, mandrills, drills, and mangabeys), for example, these factors are expected to reduce N(e) of paternally inherited portions of the genome compared to maternally inherited portions. To explore this further, we quantified relative N(e) of autosomal DNA, X and Y chromosomes, and mitochondrial DNA using molecular polymorphism and divergence information from pigtail macaque monkeys (Macaca nemestrina). Consistent with demographic expectations, we found that N(e) of the Y is lower than expected from a Wright-Fisher idealized population with an equal proportion of males and females, whereas N(e) of mitochondrial DNA is higher. However, N(e) of 11 loci on the X chromosome was lower than expected, a finding that could be explained by pervasive hitchhiking effects on this chromosome. We evaluated the fit of these data to various models involving natural selection or sex-biased demography. Significant support was recovered for natural selection acting on the Y chromosome. A demographic model with a skewed sex ratio was more likely than one with sex-biased migration and explained the data about as well as an ideal model without sex-biased demography. We then incorporated these results into an evaluation of macaque divergence and migration on Borneo and Sulawesi islands. One X-linked locus was not monophyletic on Sulawesi, but multilocus data analyzed in a coalescent framework failed to reject a model without migration between these islands after both were colonized.
性别的差异会影响扩散、存活、繁殖成功率和自然选择，从而对具有不同遗传模式的基因组区域的有效种群大小（Ne）产生不同的影响，例如性染色体和线粒体 DNA。例如，在狒狒科（猕猴、狒狒、山魈、山魈、钻地蜂和白眉猴）的灵长类动物中，这些因素预计会降低父系遗传基因组部分的 Ne，而增加母系遗传基因组部分的 Ne。为了进一步探讨这一问题，我们使用来自长尾猕猴（Macaca nemestrina）的分子多态性和分化信息，量化了常染色体 DNA、X 和 Y 染色体以及线粒体 DNA 的相对 Ne。与人口统计学预期一致，我们发现 Y 的 Ne 低于具有相同比例的雄性和雌性的 Wright-Fisher 理想种群所预期的值，而线粒体 DNA 的 Ne 则较高。然而，X 染色体上 11 个位点的 Ne 低于预期，这一发现可以用这条染色体上普遍存在的连锁漂变效应来解释。我们评估了这些数据与涉及自然选择或性别偏向性人口统计学的各种模型的拟合情况。对 Y 染色体上自然选择的支持是显著的。与性别偏向性迁移的模型相比，性别比例偏斜的人口统计学模型更有可能，并且与没有性别偏向性人口统计学的理想模型一样，能够很好地解释数据。然后，我们将这些结果纳入对婆罗洲和苏拉威西岛猕猴的分化和迁移的评估中。一个 X 连锁基因座在苏拉威西岛不是单系的，但在合并框架中分析的多基因座数据未能拒绝这两个岛屿在被殖民后没有迁移的模型。
