Balloux F, Brünner H, Lugon-Moulin N, Hausser J, Goudet J
Institut d'Ecologie, Université de Lausanne, Switzerland.
Evolution. 2000 Aug;54(4):1414-22. doi: 10.1111/j.0014-3820.2000.tb00573.x.
It has been long recognized that highly polymorphic genetic markers can lead to underestimation of divergence between populations when migration is low. Microsatellite loci, which are characterized by extremely high mutation rates, are particularly likely to be affected. Here, we report genetic differentiation estimates in a contact zone between two chromosome races of the common shrew (Sorex araneus), based on 10 autosomal microsatellites, a newly developed Y-chromosome microsatellite, and mitochondrial DNA. These results are compared to previous data on proteins and karyotypes. Estimates of genetic differentiation based on F- and R-statistics are much lower for autosomal microsatellites than for all other genetic markers. We show by simulations that this discrepancy stems mainly from the high mutation rate of microsatellite markers for F-statistics and from deviations from a single-step mutation model for R-statistics. The sex-linked genetic markers show that all gene exchange between races is mediated by females. The absence of male-mediated gene flow most likely results from male hybrid sterility.
长期以来，人们已经认识到，当迁移率较低时，高度多态的遗传标记可能会导致对种群间差异的低估。微卫星位点具有极高的突变率，尤其容易受到影响。在这里，我们报告了基于10个常染色体微卫星、一个新开发的Y染色体微卫星和线粒体DNA，对普通鼩鼱（Sorex araneus）两个染色体种族接触区的遗传分化估计。这些结果与之前关于蛋白质和核型的数据进行了比较。基于F统计量和R统计量的遗传分化估计，常染色体微卫星比所有其他遗传标记要低得多。我们通过模拟表明，这种差异主要源于F统计量中微卫星标记的高突变率以及R统计量中偏离单步突变模型。性连锁遗传标记表明，种族之间的所有基因交换都是由雌性介导的。雄性介导的基因流动缺失很可能是由于雄性杂种不育。
