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研究揭示同域性物种形成过程中基因组差异的对比特征
2020-10-31 20:34

德国康斯坦茨大学Axel Meyer小组揭示出同域性物种形成过程中基因组差异的对比特征。相关论文于2020年10月28日在线发表在《自然》杂志上。

在新热带丽鱼科鱼类(Amphilophus spp.)的一个年轻物物种中,研究人员分析了群体和物种之间的基因组差异。通过产生一个新的基因组装配并重新测序453个基因组,研究人员发现了性状的遗传结构,这被认为对差异很重要。影响生态性能和/或配偶选择的单基因或寡聚性状不同的物种显示出明显的局部基因组分化。相比之下,已在多基因性状上有所不同的物种之间的分化在基因组上是广泛分布的,总体上要高得多,这与有效且稳定的全基因组全基因障碍的进化一致。因此,研究人员得出的结论是,简单的性状体系结构并不总是像以前建议的那样有利于利用基因流进行物种形成,而多基因体系结构可以促进共生的快速和稳定的物种形成。

据了解,自达尔文以来,进化生物学家一直对一个问题感到困惑:从单一物种的“特征鲜明的品种”到“定义明确的物种”的转变是如何实现的,尤其是在没有基因流动的地理障碍(同族物种形成)情况下。基因流抵消了全基因组分化的积累,这是物种形成的标志,并增加了完成物种形成过程的不可逆转的生殖屏障(不相容性)进化的可能性。理论预测,不同选择性状的遗传结构会影响同伴物种的形成是否发生,但由于其独特的生物学和进化史,难以收集和综合不同物种的数据,因此对这一理论的实证检验很少。

附:英文原文

Title: Contrasting signatures of genomic divergence during sympatric speciation

Author: Andreas F. Kautt, Claudius F. Kratochwil, Alexander Nater, Gonzalo Machado-Schiaffino, Melisa Olave, Frederico Henning, Julin Torres-Dowdall, Andreas Hrer, C. Darrin Hulsey, Paolo Franchini, Martin Pippel, Eugene W. Myers, Axel Meyer

Issue&Volume: 2020-10-28

Abstract: The transition from ‘well-marked varieties’ of a single species into ‘well-defined species’—especially in the absence of geographic barriers to gene flow (sympatric speciation)—has puzzled evolutionary biologists ever since Darwin1,2. Gene flow counteracts the buildup of genome-wide differentiation, which is a hallmark of speciation and increases the likelihood of the evolution of irreversible reproductive barriers (incompatibilities) that complete the speciation process3. Theory predicts that the genetic architecture of divergently selected traits can influence whether sympatric speciation occurs4, but empirical tests of this theory are scant because comprehensive data are difficult to collect and synthesize across species, owing to their unique biologies and evolutionary histories5. Here, within a young species complex of neotropical cichlid fishes (Amphilophus spp.), we analysed genomic divergence among populations and species. By generating a new genome assembly and re-sequencing 453 genomes, we uncovered the genetic architecture of traits that have been suggested to be important for divergence. Species that differ in monogenic or oligogenic traits that affect ecological performance and/or mate choice show remarkably localized genomic differentiation. By contrast, differentiation among species that have diverged in polygenic traits is genomically widespread and much higher overall, consistent with the evolution of effective and stable genome-wide barriers to gene flow. Thus, we conclude that simple trait architectures are not always as conducive to speciation with gene flow as previously suggested, whereas polygenic architectures can promote rapid and stable speciation in sympatry.

DOI: 10.1038/s41586-020-2845-0

Source: https://www.nature.com/articles/s41586-020-2845-0

Nature:《自然》,创刊于1869年。隶属于施普林格·自然出版集团,最新IF:43.07
官方网址:http://www.nature.com/
投稿链接:http://www.nature.com/authors/submit_manuscript.html


本期文章:《自然》:Online/在线发表

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