Rapid phenotypic evolution during incipient speciation in a continental avian radiation
Rapid phenotypic evolution during incipient speciation in a continental avian radiation
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DOI：
10.1098/rspb.2011.2170
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发表时间：
2012-05-07
影响因子：
4.7
通讯作者：
Tubaro, Pablo L.
中科院分区：
文献类型：
--
作者：
Campagna, Leonardo;Benites, Pilar;Tubaro, Pablo L.
适应性辐射帮助塑造了我们对动物物种形成的看法，特别是达尔文雀、夏威夷果蝇和非洲五大湖慈济鱼等经典例子。这些“岛状”辐射是相对较新的，这使得它们特别有趣，因为导致多样性的机制仍在运行。在这里，我们在一个大陆分布的物种群中发现了一个最近发生的鸟类辐射的新病例；Capuchino种子库包括11个嗜孢子虫物种，最初是根据成年雄性羽毛颜色和图案的差异来描述的。我们使用分子数据以及雄性羽毛和发声的分析来了解该群体的物种限制。我们发现了明显的表型变异，尽管缺乏线粒体DNA，而且在其他假定中性的核标记上几乎没有差异。这一发现与该群体最近从更新世开始经历的辐射是一致的，留下了不完整的谱系排序、渐进式杂交和人口扩张的遗传特征。我们认为，中性DNA同质性和表型多样性之间的这种明显的解偶联对于最近在合并理论框架内的一个群体是可望的。最后，我们讨论了更新世南美洲开放栖息地的生态如何有助于促进这种独特的和持续的辐射。
Adaptive radiations have helped shape how we view animal speciation, particularly classic examples such as Darwin's finches, Hawaiian fruitflies and African Great Lakes cichlids. These 'island' radiations are comparatively recent, making them particularly interesting because the mechanisms that caused diversification are still in motion. Here, we identify a new case of a recent bird radiation within a continentally distributed species group; the capuchino seedeaters comprise 11 Sporophila species originally described on the basis of differences in plumage colour and pattern in adult males. We use molecular data together with analyses of male plumage and vocalizations to understand species limits of the group. We find marked phenotypic variation despite lack of mitochondrial DNA monophyly and few differences in other putatively neutral nuclear markers. This finding is consistent with the group having undergone a recent radiation beginning in the Pleistocene, leaving genetic signatures of incomplete lineage sorting, introgressive hybridization and demographic expansions. We argue that this apparent uncoupling between neutral DNA homogeneity and phenotypic diversity is expected for a recent group within the framework of coalescent theory. Finally, we discuss how the ecology of open habitats in South America during the Pleistocene could have helped promote this unique and ongoing radiation.