Variable Signatures of Selection Despite Conserved Recombination Landscapes Early in Speciation
Variable Signatures of Selection Despite Conserved Recombination Landscapes Early in Speciation
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尽管在物种形成早期保留了保守的重组景观，但选择的可变特征
DOI：
10.1093/jhered/esab054
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发表时间：
2021
影响因子：
3.1
通讯作者：
Taylor, Scott A
中科院分区：
文献类型：
--
作者：
Turbek, Sheela P;Semenov, Georgy A;Enbody, Erik D;Campagna, Leonardo;Taylor, Scott A
最近分化的类群往往表现出异质景观的基因组分化，其特征是在其他同质的背景上分化升高的区域。虽然分歧峰通常被解释为负责生殖隔离的区域，但它们也可能是由于背景选择，与物种形成无关的选择性扫描以及重组和突变率的变化而出现的。为了研究在物种形成的早期阶段的重组模式和景观的基因组分化之间的关联，我们产生了细尺度的重组地图为6个南方卷尾猴seedeater（Sporophila）和两个亚种的白色Wagtail（Motacilla alba），最近的两个鸟类辐射中，不同的选择色素基因可能产生分化的高峰。我们比较了这些重组地图的有领（Ficedula albicollis）和斑捕蝇（Ficedula hypoleuca），非姐妹类群的特点是适度的基因组分化和异质景观的基因组分化形成的背景选择的一部分。尽管重组景观在所有三个系统中都是保守的，但我们记录了最近辐射中重组率与基因组分化之间较弱的负相关性。卷尾猴，wagtails，和flycatchers之间的所有分歧峰位于低于平均重组率的地区，和卷尾猴和flycatchers的分歧峰落在异常减少重组的地区。因此，在这些地区的共适应等位基因组合可能已经保护早期分歧，促进快速多样化。尽管在很大程度上保守的重组景观，发散峰是特定的每个焦点比较卷尾猴，这表明该地区的分化升高还没有产生的重组率的变化。
Recently diverged taxa often exhibit heterogeneous landscapes of genomic differentiation, characterized by regions of elevated differentiation on an otherwise homogeneous background. While divergence peaks are generally interpreted as regions responsible for reproductive isolation, they can also arise due to background selection, selective sweeps unrelated to speciation, and variation in recombination and mutation rates. To investigate the association between patterns of recombination and landscapes of genomic differentiation during the early stages of speciation, we generated fine-scale recombination maps for six southern capuchino seedeaters (Sporophila) and two subspecies of White Wagtail (Motacilla alba), two recent avian radiations in which divergent selection on pigmentation genes has likely generated peaks of differentiation. We compared these recombination maps to those of Collared (Ficedula albicollis) and Pied Flycatchers (Ficedula hypoleuca), non-sister taxa characterized by moderate genomic divergence and a heterogenous landscape of genomic differentiation shaped in part by background selection. Although recombination landscapes were conserved within all three systems, we documented a weaker negative correlation between recombination rate and genomic differentiation in the recent radiations. All divergence peaks between capuchinos, wagtails, and flycatchers were located in regions with lower-than-average recombination rates, and most divergence peaks in capuchinos and flycatchers fell in regions of exceptionally reduced recombination. Thus, co-adapted allelic combinations in these regions may have been protected early in divergence, facilitating rapid diversification. Despite largely conserved recombination landscapes, divergence peaks are specific to each focal comparison in capuchinos, suggesting that regions of elevated differentiation have not been generated by variation in recombination rate alone.