Linked selection, demography and the evolution of correlated genomic landscapes in birds and beyond
Linked selection, demography and the evolution of correlated genomic landscapes in birds and beyond
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DOI：
10.1111/mec.14167
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发表时间：
2017-08-01
影响因子：
4.9
通讯作者：
Burri, Reto
中科院分区：
文献类型：
--
作者：
Burri, Reto
选择对遗传多样性和种群分化沿着基因组（多样性和分化的基因组景观）的分布有着深刻的影响，不仅在它所针对的位点，而且在相连的中性位点，减少了多样性，提高了分化。在高通量测序革命的推动下，这些选择的基因组足迹在过去十年中得到了广泛的利用，目的是确定参与适应和物种形成的基因组区域。然而，虽然这项研究表明多样性和分化的基因组景观通常是高度异质性的，但它也让人们越来越认识到这种异质性可能会在适应或物种形成以外的过程中进化。特别是，不是选择性扫描或基因流动的障碍的影响，强调分化可以通过减少基因组内局部遗传多样性的任何过程进化（Charlesworth，1998），包括在链接位点的纯化选择（背景选择）。特别是，在重组不频繁的基因组区域，分化加剧可能是与适应或物种形成无关的多样性减少的副产品（Cruickshank & Hahn，2014; Nachman & Payseur，2012; Noor &班尼特，2009）。在这样的基因组区域中，连锁在物理上更大的基因组延伸，并且选择影响特别高数量的连锁中性位点。尽管选择对连锁中性多样性的影响种群内的连锁选择（连锁选择）已得到充分记录（Cutter & Payseur，2013），最近对即使在独立谱系之间也高度相关的多样性和分化景观的观察表明，长期连锁选择的影响可能会对进化产生更深的影响比之前预期的多样性和分化的基因组景观。货车Doren等人（2017年）在本期《分子生态学》杂志上报道了对石房蛤属石雀的研究，该研究与这一方向迅速扩大的证据相一致。基因组景观的相关性从石猫内部延伸到与Ficedula flycatchers的比较，增加了最近对连锁选择持续影响的时间尺度的见解。另一方面，在涉及岛屿分类单元的比较中，基因组景观的不存在和反向相关性提供了重要的经验线索，说明人口限制在基因组景观多样性和分化的进化中的作用。
Selection has a deep impact on the distribution of genetic diversity and population differentiation along the genome (the genomic landscapes of diversity and differentiation), reducing diversity and elevating differentiation not only at the sites it targets, but also at linked neutral sites. Fuelled by the high-throughput sequencing revolution, these genomic footprints of selection have been extensively exploited over the past decade with the aim to identify genomic regions involved in adaptation and speciation. However, while this research has shown that the genomic landscapes of diversity and differentiation are usually highly heterogeneous, it has also led to the increasing realization that this heterogeneity may evolve under processes other than adaptation or speciation. In particular, instead of being an effect of selective sweeps or barriers to gene flow, accentuated differentiation can evolve by any process reducing genetic diversity locally within the genome (Charlesworth, 1998), including purifying selection at linked sites (background selection). In particular, in genomic regions where recombination is infrequent, accentuated differentiation can evolve as a by-product of diversity reductions unrelated to adaptation or speciation (Cruickshank & Hahn, 2014; Nachman & Payseur, 2012; Noor & Bennett, 2009). In such genomic regions, linkage extends over physically larger genome stretches, and selection affects a particularly high number of linked neutral sites. Even though the effects of selection on linked neutral diversity (linked selection) within populations are well documented (Cutter & Payseur, 2013), recent observations of diversity and differentiation landscapes that are highly correlated even among independent lineages suggest that the effects of long-term linked selection may have a deeper impact on the evolution of the genomic landscapes of diversity and differentiation than previously anticipated. The study on Saxicola stonechats by Van Doren et al. (2017) reported in the current issue of Molecular Ecology lines in with a rapidly expanding body of evidence in this direction. Correlations of genomic landscapes extending from within stonechats to comparisons with Ficedula flycatchers add to recent insights into the timescales across which the effects of linked selection persist. Absent and inverted correlations of genomic landscapes in comparisons involving an island taxon, on the other hand, provide important empirical clues about the role of demographic constraints in the evolution of the genomic landscapes of diversity and differentiation.