Global adaptation complicates the interpretation of genome scans for local adaptation.
Global adaptation complicates the interpretation of genome scans for local adaptation.
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全球适应使对局部适应的基因组扫描的解释变得复杂。
DOI：
10.1002/evl3.208
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发表时间：
2021-03
影响因子：
5
通讯作者：
Whitlock MC
中科院分区：
文献类型：
--
作者：
Booker TR;Yeaman S;Whitlock MC
空间变化的选择促进了等位基因频率的变化，增加了集合种群中部落之间的遗传分化。出于这个原因，测量遗传分化的汇总统计量（如FST）的全基因组分布中的离群值通常被解释为有助于局部适应的等位基因的证据。然而，理论研究表明，在空间结构的群体中，具有空间均匀适应性效应的有益突变的传播也可以诱导瞬时遗传分化。近年来，许多实证研究表明，这种物种范围内或全球性的适应对分子进化做出了重大贡献。从这个角度来看，我们讨论了这种全局适应如何影响FST的全基因组分布并产生遗传分化模式，这可能被误认为是局部适应。为了说明这一点，我们使用了时间向前的群体遗传模拟，假设有益突变的速率和强度的参数与自然群体的估计值一致。我们证明，全球范围内的有益突变的传播在儿科人群中可能会经常产生FST离群值，这可能被误解为当地适应的证据。有益突变的传播导致侧翼位点的选择性扫描，因此在某些情况下，除了FST之外，还可以通过检查种群内和种群之间的核苷酸多样性模式来区分全局与局部适应的影响。然而，当局部适应最近才建立时，由于侧翼位点的连锁不平衡积累较少，因此可能更难以与全局适应区分开。通过我们的讨论，我们的结论是，很大一部分FST离群值，被认为是产生于局部适应，而不是由于全球适应。
Spatially varying selection promotes variance in allele frequencies, increasing genetic differentiation between the demes of a metapopulation. For that reason, outliers in the genome‐wide distribution of summary statistics measuring genetic differentiation, such as FST, are often interpreted as evidence for alleles that contribute to local adaptation. However, theoretical studies have shown that in spatially structured populations the spread of beneficial mutations with spatially uniform fitness effects can also induce transient genetic differentiation. In recent years, numerous empirical studies have suggested that such species‐wide, or global, adaptation makes a substantial contribution to molecular evolution. In this perspective, we discuss how commonly such global adaptation may influence the genome‐wide distribution of FST and generate genetic differentiation patterns, which could be mistaken for local adaptation. To illustrate this, we use forward‐in‐time population genetic simulations assuming parameters for the rate and strength of beneficial mutations consistent with estimates from natural populations. We demonstrate that the spread of globally beneficial mutations in parapatric populations may frequently generate FST outliers, which could be misinterpreted as evidence for local adaptation. The spread of beneficial mutations causes selective sweeps at flanking sites, so in some cases, the effects of global versus local adaptation may be distinguished by examining patterns of nucleotide diversity within and between populations in addition to FST. However, when local adaptation has been only recently established, it may be much more difficult to distinguish from global adaptation, due to less accumulation of linkage disequilibrium at flanking sites. Through our discussion, we conclude that a large fraction of FST outliers that are presumed to arise from local adaptation may instead be due to global adaptation.