The impact of population expansion and mutation rate heterogeneity on DNA sequence polymorphism
The impact of population expansion and mutation rate heterogeneity on DNA sequence polymorphism
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DOI：
10.1093/oxfordjournals.molbev.a025610
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发表时间：
1996-03-01
影响因子：
10.7
通讯作者：
Excoffier, L
中科院分区：
文献类型：
--
作者：
ArisBrosou, S;Excoffier, L
为了研究突变率异质性对 DNA 多态性模式的影响，我们模拟了静止群体和扩张群体中具有 γ 分布核苷酸取代率的 DNA 序列样本。我们发现，最近的种群扩张和突变率异质性对几个多态性指标有类似的影响，例如观察到的成对差异分布的形状和平均值，或分离位点的数量。因此，如果核苷酸具有不同的替代率，则推断的种群扩张规模似乎会被高估。有趣的是，当单独作用时，种群扩张和不均匀突变率对 Tajima 的 D 统计量具有相反的影响，并且研究了选择性中性相关检验的结果。对几个人类群体线粒体控制区域的多态性模式进行了检查，主要表明难以量化过去人口历史的各自贡献和来自单个采样进化过程的不均匀突变率。然而，在控制区的第二个高变片段中，取代率显得比第一个片段更加异质。
In order to study the effect of mutation rate heterogeneity on patterns of DNA polymorphism, we simulated samples of DNA sequences with gamma-distributed nucleotide substitution rates in stationary and expanding populations. We find that recent population expansions and mutation rate heterogeneity have similar effects on several polymorphism indicators, like the shape and the mean of the observed pairwise difference distribution, or the number of segregating sites. The inferred size of population expansion thus appears overestimated if nucleotides have dissimilar substitution rates. Interestingly, population expansion and uneven mutation rates have contrasting effects on Tajima's D statistic when acting separately, and the consequence on the associated test of selective neutrality is investigated. The patterns of polymorphism of several human populations analyzed for the mitochondrial control region are examined, mainly showing the difficulty in quantifying the respective contribution of past demographic history and uneven mutation rates from a single sampled evolutionary process. However, substitution rates appear more heterogeneous in the second hypervariable segment of the control region than in the first segment.