Laboratoire d'Excellence «CORAIL», EPHE, PSL Research University, UPVD, CNRS, USR 3278 CRIOBE, F-66360 Perpignan, France.
Instituto de Ciencias Ambientales y Evolutivas, Universidad Austral de Chile, Valdivia, Chile.
Sci Rep. 2017 Jan 16;7:40519. doi: 10.1038/srep40519.
Despite the unique nature of endemic species, their origin and population history remain poorly studied. We investigated the population history of 28 coral reef fish species, close related, from the Gambier and Marquesas Islands, from five families, with range size varying from widespread to small-range endemic. We analyzed both mitochondrial and nuclear sequence data using neutrality test and Bayesian analysis (EBSP and ABC). We found evidence for demographic expansions for most species (24 of 28), irrespective of range size, reproduction strategy or archipelago. The timing of the expansions varied greatly among species, from 8,000 to 2,000,000 years ago. The typical hypothesis for reef fish that links population expansions to the Last Glacial Maximum fit for 14 of the 24 demographic expansions. We propose two evolutionary processes that could lead to expansions older than the LGM: (a) we are retrieving the signature of an old colonization process for widespread, large-range endemic and paleoendemic species or (b) speciation; the expansion reflects the birth of the species for neoendemic species. We show for the first time that the demographic histories of endemic and widespread reef fish are not distinctly different and suggest that a number of processes drive endemism.
尽管特有种具有独特的性质，但它们的起源和种群历史仍未得到充分研究。我们调查了来自 Gambier 和 Marquesas 群岛的五个科的 28 种珊瑚礁鱼类近缘种的种群历史，这些鱼类的分布范围从广泛到小范围特有。我们使用中性检验和贝叶斯分析（EBSP 和 ABC）分析了线粒体和核序列数据。我们发现大多数物种（28 种中的 24 种）都存在种群扩张的证据，而不论其分布范围大小、繁殖策略或群岛情况如何。扩张的时间差异很大，从 8000 年前到 200 万年前不等。与末次冰期最大值相关的珊瑚鱼种群扩张的典型假设适用于 24 个种群扩张中的 14 个。我们提出了两个可能导致扩张时间早于 LGM 的进化过程：（a）我们正在恢复广泛分布、大范围特有和古特有物种的古老殖民过程的特征，或（b）物种形成；扩张反映了新特有种的诞生。我们首次表明，特有种和广泛分布的珊瑚鱼的种群历史没有明显的区别，并表明许多过程导致了特有现象。
