Sağlam İsmaİl K, Baumsteiger Jason, Smith Matt J, Linares-Casenave Javier, Nichols Andrew L, O'Rourke Sean M, Miller Michael R
Department of Animal Science, University of California, One Shields Avenue, Davis, CA, 95616, USA.
Ecological Sciences Research Laboratories, Department of Biology, Hacettepe University, Beytepe, 06800, Ankara, Turkey.
Mol Ecol. 2016 Aug;25(16):3962-73. doi: 10.1111/mec.13732. Epub 2016 Jul 9.
The Devils Hole pupfish (Cyprinodon diabolis; DHP) is an icon of conservation biology. Isolated in a 50 m(2) pool (Devils Hole), DHP is one of the rarest vertebrate species known and an evolutionary anomaly, having survived in complete isolation for thousands of years. However, recent findings suggest DHP might be younger than commonly thought, potentially introduced to Devils Hole by humans in the past thousand years. As a result, the significance of DHP from an evolutionary and conservation perspective has been questioned. Here we present a high-resolution genomic analysis of DHP and two closely related species, with the goal of thoroughly examining the temporal divergence of DHP. To this end, we inferred the evolutionary history of DHP from multiple random genomic subsets and evaluated four historical scenarios using the multispecies coalescent. Our results provide substantial information regarding the evolutionary history of DHP. Genomic patterns of secondary contact present strong evidence that DHP were isolated in Devils Hole prior to 20-10 ka and the model best supported by geological history and known mutation rates predicts DHP diverged around 60 ka, approximately the same time Devils Hole opened to the surface. We make the novel prediction that DHP colonized and have survived in Devils Hole since the cavern opened, and the two events (colonization and collapse of the cavern's roof) were caused by a common geologic event. Our results emphasize the power of evolutionary theory as a predictive framework and reaffirm DHP as an important evolutionary novelty, worthy of continued conservation and exploration.
魔洞鳉（Cyprinodon diabolis；DHP）是保护生物学的一个标志性物种。它孤立于一个50平方米的水池（魔洞）中，是已知最稀有的脊椎动物物种之一，也是一个进化异常现象，在完全隔离的状态下存活了数千年。然而，最近的研究结果表明，魔洞鳉可能比通常认为的更年轻，有可能是在过去一千年里被人类引入魔洞的。因此，从进化和保护的角度来看，魔洞鳉的重要性受到了质疑。在这里，我们展示了对魔洞鳉和两个近缘物种的高分辨率基因组分析，目的是全面研究魔洞鳉的时间分化。为此，我们从多个随机基因组子集中推断出魔洞鳉的进化历史，并使用多物种溯祖法评估了四种历史情景。我们的结果提供了关于魔洞鳉进化历史的大量信息。二次接触的基因组模式提供了强有力的证据，表明魔洞鳉在20 - 10千年前就已在魔洞中隔离，并且由地质历史和已知突变率最佳支持的模型预测魔洞鳉在大约60千年前分化，大约与魔洞向地表开放的时间相同。我们做出了一个新的预测，即自从洞穴开放以来，魔洞鳉就已在魔洞中定殖并存活下来，而且这两个事件（定殖和洞穴顶部坍塌）是由一个共同的地质事件引起的。我们的结果强调了进化理论作为一个预测框架的力量，并重申魔洞鳉是一个重要的进化新物种，值得继续加以保护和探索。
