Maintenance of Species Boundaries Despite Ongoing Gene Flow in Ragworts.
Maintenance of Species Boundaries Despite Ongoing Gene Flow in Ragworts.
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DOI：
10.1093/gbe/evw053
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发表时间：
2016-04-13
影响因子：
3.3
通讯作者：
Filatov DA
中科院分区：
文献类型：
--
作者：
Osborne OG;Chapman MA;Nevado B;Filatov DA
不同物种间杂交的作用一直是最近大量进化研究的焦点。虽然基因流动可以阻止物种形成或引发物种崩溃，但它也可以产生新的杂交物种。同样，虽然适应性分化可以通过基因流动消除，但新的适应性变异可以通过基因渗入引入。这些结果的相对频率，以及杂交和基因渗入的频率在很大程度上是未知的。一组密切相关的物种与几个记录的杂交案例是地中海的ragwort（属：Senecio）种-复合体。多倍体和同倍体杂交物种形成的例子在进化枝中是已知的，尽管它们的进化关系和它们之间渐渗杂交的一般频率仍然未知。利用包含八个Senecio物种的全基因组基因空间数据集，我们首次完全解决了这些物种的系统发育问题，尽管整个基因组的系统发育不一致。使用d统计方法，我们证明了以前未知的物种树中多对分类群之间的渐进杂交情况。这是将这些物种建立为基因流多样化研究体系的重要一步，表明渐渗杂交可能是植物进化中广泛而重要的过程。
The role of hybridization between diversifying species has been the focus of a huge amount of recent evolutionary research. While gene flow can prevent speciation or initiate species collapse, it can also generate new hybrid species. Similarly, while adaptive divergence can be wiped out by gene flow, new adaptive variation can be introduced via introgression. The relative frequency of these outcomes, and indeed the frequency of hybridization and introgression in general are largely unknown. One group of closely-related species with several documented cases of hybridization is the Mediterranean ragwort (genus: Senecio) species-complex. Examples of both polyploid and homoploid hybrid speciation are known in the clade, although their evolutionary relationships and the general frequency of introgressive hybridization among them remain unknown. Using a whole genome gene–space dataset comprising eight Senecio species we fully resolve the phylogeny of these species for the first time despite phylogenetic incongruence across the genome. Using a D-statistic approach, we demonstrate previously unknown cases of introgressive hybridization between multiple pairs of taxa across the species tree. This is an important step in establishing these species as a study system for diversification with gene flow, and suggests that introgressive hybridization may be a widespread and important process in plant evolution.