Genetic consequences of sequential founder events by an island-colonizing bird
Genetic consequences of sequential founder events by an island-colonizing bird
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DOI：
10.1073/pnas.102583399
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发表时间：
2002-06-11
影响因子：
11.1
通讯作者：
Owens, IPF
中科院分区：
文献类型：
--
作者：
Clegg, SM;Degnan, SM;Owens, IPF
创始人事件在促进岛屿进化变化方面的重要性一直是长期争论的主题。由于缺乏来自自然形成的岛屿人口的经验证据，这一辩论的解决受到阻碍。在这里，我们进行了一系列的历史记载，自然殖民事件的silvereye物种复杂（Zosterops lateralis），一组用于说明岛屿殖民化的过程中，在原来的创始人效应模型的遗传分析。我们的研究结果表明，单一的创始人事件不影响杂合性或等位基因多样性的水平，也不会导致种群之间的直接遗传分化。相反，需要四到五个连续的创始人事件之前，多样性和分歧的指数的方法，看到在进化的旧形式。基于计算机模拟的贝叶斯分析可以推断出有效的创始人的数量，并表明创始人的影响是弱的，因为岛屿人口建立从相对较大的羊群。事实上，统计支持创始人事件模型并没有显着高于所有最近殖民岛屿的逐渐漂移模型。两者合计，这些结果表明，在这个物种复杂的单一殖民化事件很少伴随着严重的创始人效应，和多个创始人事件和/或长期的遗传漂变已中性遗传多样性的后果更大。
The importance of founder events in promoting evolutionary changes on islands has been a subject of long-running controversy. Resolution of this debate has been hindered by a lack of empirical evidence from naturally founded island populations. Here we undertake a genetic analysis of a series of historically documented, natural colonization events by the silvereye species-complex (Zosterops lateralis), a group used to illustrate the process of island colonization in the original founder effect model. Our results indicate that single founder events do not affect levels of heterozygosity or allelic diversity, nor do they result in immediate genetic differentiation between populations. Instead, four to five successive founder events are required before indices of diversity and divergence approach that seen in evolutionarily old forms. A Bayesian analysis based on computer simulation allows inferences to be made on the number of effective founders and indicates that founder effects are weak because island populations are established from relatively large flocks. Indeed, statistical support for a founder event model was not significantly higher than for a gradual-drift model for all recently colonized islands. Taken together, these results suggest that single colonization events in this species complex are rarely accompanied by severe founder effects, and multiple founder events and/or long-term genetic drift have been of greater consequence for neutral genetic diversity.