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Does gene flow between species play a role in island adaptive radiations?

物种之间的基因流动在岛屿适应性辐射中发挥作用吗？

基本信息

批准号：
NE/E00489X/1
负责人：
Dmitry Filatov
金额：
$ 40.11万
依托单位：
University of Oxford
依托单位国家：
英国
项目类别：
Research Grant
财政年份：
2007
资助国家：
英国
起止时间：
2007 至无数据
项目状态：
已结题

来源：
https://gtr.ukri.org/projects?ref=NE%2FE00489X%2F1
关键词：
Does gene flow between species

项目摘要

The extremely fast rate of phenotypic and ecological adaptation of species during 'explosive' adaptive radiations on islands remains one of the most intriguing evolutionary phenomena. Low genetic diversity of island populations may present an obstacle for fast adaptive changes, as natural selection needs genetic variation from which to select. Hybridisation of closely related species and interspecific gene flow may provide the genetic variation needed for natural selection. Although multiple cases of interspecific hybridisation are known, there is little evidence that it may play a role in adaptive evolution. We will use the Hawaiian endemic plant genus Schiedea (Caryophyllaceae) to infer the role of interspecific gene flow in adaptive radiation. This genus presents one of the most impressive recent adaptive radiations in plants, as it has evolved very diverse morphological forms (ranging from vines to perennial herbes and woody bushes) and colonised a wide range of ecological niches in just a few million years. To assess the role of gene flow between the species during adaptive radiation in Schiedea we will (i) estimate what proportion of genes show evidence for interspecific introgression, and (ii) test whether positive selection could have caused the spread of genes across several species. The spread of a positively selected allele across several species should distort the phylogeny of that gene, making it incompatible with the phylogenies of other genes not affected by interspecific introgression. We will estimate the proportion of genes with distorted phylogenies in genus Schiedea and will test whether the distortion could have been caused by the spread of advantageous alleles across several species.

在岛屿上的“爆炸性”适应性辐射期间，物种的表型和生态适应速度极快，仍然是最有趣的进化现象之一。岛屿人口的遗传多样性低可能对快速适应性变化构成障碍，因为自然选择需要遗传变异来进行选择。近缘物种的杂交和种间基因流可能为自然选择提供所需的遗传变异。虽然已知多种种间杂交的情况，但很少有证据表明它可能在适应性进化中发挥作用。我们将使用夏威夷特有的植物属Schiedea（嘉鱼科）来推断种间基因流在适应性辐射中的作用。该属是最近植物中最令人印象深刻的适应辐射之一，因为它已经进化出非常多样的形态（从藤本植物到多年生草本植物和木本灌木），并在短短几百万年内殖民了广泛的生态位。为了评估Schiedea适应性辐射过程中物种间基因流的作用，我们将（i）估计基因的比例显示种间渐渗的证据，（ii）测试是否积极选择可能导致跨几个物种的基因传播。一个正选择的等位基因在几个物种中的传播应该会扭曲该基因的遗传，使其与其他不受种间渐渗影响的基因的遗传不相容。我们将估计Schiedea属中具有扭曲等位基因的基因的比例，并将测试这种扭曲是否可能是由优势等位基因在几个物种中的传播引起的。