Genomic evidence of survival near ice sheet margins for some, but not all, North American trees
Genomic evidence of survival near ice sheet margins for some, but not all, North American trees
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DOI：
10.1073/pnas.1901656116
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发表时间：
2019-04-23
影响因子：
11.1
通讯作者：
Dick, Christopher W.
中科院分区：
文献类型：
--
作者：
Bemmels, Jordan B.;Knowles, L. Lacey;Dick, Christopher W.
温带物种经历了戏剧性的范围减少在最后。冰川最大，但避难所人口的现代人口的后裔从来没有被精确定位。基于气候的模型只能确定广阔的潜在栖息地，传统的植物地理学研究提供的空间分辨率很差，温带森林群落的花粉记录很难解释，也不能提供物种级别的分类分辨率。在这里，我们利用大型基因组数据集的范围扩展信号，使用基于模拟的框架来推断两个广泛分布的山核桃（山核桃属）中冰川避难所的精确纬度和经度。并量化这些估计中的不确定性。我们发现，一个物种可能扩大从接近冰盖边缘附近的网站以前描述的宏化石属，突出支持有争议的概念北方microrefugia。与此相反，第二个物种推断的扩张起源是兼容的经典假说的遥远的位移到南部避难所。我们的统计学严谨，强大的方法展示了如何从基因组数据中以高精度和准确度定位避难所，解决有关长期应对气候变化的基本问题，并为以前主要定性解决的长期问题提供统计学见解。
Temperate species experienced dramatic range reductions during the Last. Glacial Maximum, yet refugial populations from which modern populations are descended have never been precisely located. Climate-based models identify only broad areas of potential habitat, traditional phylogeographic studies provide poor spatial resolution, and pollen records for temperate forest communities are difficult to interpret and do not provide species-level taxonomic resolution. Here we harness signals of range expansion from large genomic datasets, using a simulation-based framework to infer the precise latitude and longitude of glacial refugia in two widespread, codistributed hickories (Carya spp.) and to quantify uncertainty in these estimates. We show that one species likely expanded from close to ice sheet margins near the site of a previously described macrofossil for the genus, highlighting support for the controversial notion of northern microrefugia. In contrast, the expansion origin inferred for the second species is compatible with classic hypotheses of distant displacement into southern refugia. Our statistically rigorous, powerful approach demonstrates how refugia can be located from genomic data with high precision and accuracy, addressing fundamental questions about long-term responses to changing climates and providing statistical insight into longstanding questions that have previously been addressed primarily qualitatively.