arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 1206.6768q-bio.PE
收藏

从深度种群多样性数据估计选择性扫描的强度

Estimating the Strength of Selective Sweeps from Deep Population Diversity Data

Philipp W. Messer, Richard A. Neher

摘要:

选择性清除通常与适应位点周围的遗传多样性〈动〉性<动>的局部减少有关。然而,选择性扫描也可以快速携带中性突变,以观察到的群体频率,如果它们在扫描早期出现并与适应性等位基因搭便车。我们发现,突变和指数扩增之间的相互作用,通过搭便车的结果在所产生的新的单倍型变异的特征频谱,仅取决于扫描的突变率和选择系数的比率。基于这一结果,我们开发了一个估计的选择系数驱动扫描。由于该估计量利用了扫描期间突变产生的新变异,因此它不依赖于预先存在的变异,并且也可以应用于缺乏重组的基因座。与标准的方法,推断选择系数的大小下降的遗传多样性〈动〉性<动>周围的适应性网站相比,我们的估计需要更短的序列,但在高人口深度采样,以捕捉低频变异,鉴于这样的数据,它始终优于标准的方法。我们调查分析和数值计算的准确性,我们的估计是如何影响的扫描模式随时间的衰减作为一个后果的随机遗传漂变,并讨论重组,软扫描,和人口的潜在影响。作为其使用的一个例子,我们将我们的估计量应用于HIV人群的深度测序数据。

英文摘要:

Selective sweeps are typically associated with a local reduction of genetic diversity around the adaptive site. However, selective sweeps can also quickly carry neutral mutations to observable population frequencies if they arise early in a sweep and hitchhike with the adaptive allele. We show that the interplay between mutation and exponential amplification through hitchhiking results in a characteristic frequency spectrum of the resulting novel haplotype variation that depends only on the ratio of the mutation rate and the selection coefficient of the sweep. Based on this result, we develop an estimator for the selection coefficient driving a sweep. Since this estimator utilizes the novel variation arising from mutations during a sweep, it does not rely on preexisting variation and can also be applied to loci that lack recombination. Compared with standard approaches that infer selection coefficients from the size of dips in genetic diversity around the adaptive site, our estimator requires much shorter sequences but sampled at high population depth in order to capture low-frequency variants; given such data, it consistently outperforms standard approaches. We investigate analytically and numerically how the accuracy of our estimator is affected by the decay of the sweep pattern over time as a consequence of random genetic drift and discuss potential effects of recombination, soft sweeps, and demography. As an example for its use, we apply our estimator to deep sequencing data from HIV populations.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

↑