Terminal Pleistocene Alaskan genome reveals first founding population of Native Americans
Terminal Pleistocene Alaskan genome reveals first founding population of Native Americans
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DOI：
10.1038/nature25173
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发表时间：
2018-01-11
期刊：
影响因子：
64.8
通讯作者：
Willerslev, Eske
中科院分区：
文献类型：
--
作者：
Moreno-Mayar, J. Victor;Potter, Ben A.;Willerslev, Eske
尽管人们普遍认为美洲最初是通过白令海（Beringia）来居住的，白令海是更新世时期连接东北亚和北美西北部的陆桥，但美洲的人口何时以及如何出现仍然没有解决（1-5）。对晚更新世阿拉斯加人类遗骸的分析对于解决这些人口的时间和分散非常重要。两个婴儿的遗骸在向上太阳河（USR）被发现，并已被追溯到大约11500年前（ka）（6）。在这里，通过对USR 1基因组进行测序，平均覆盖率约为17倍，我们表明USR 1与美洲原住民关系最密切，但福尔斯与所有先前测序的当代和古代美洲原住民关系最密切（1，7，8）。因此，USR 1代表了一个独特的古白令人种群。使用人口模型，我们推断古代白令人人口和其他美洲原住民的祖先来自一个单一的创始人口，最初从东亚人分裂约36 +/- 1.5 ka，基因流持续到约25 +/- 1.1 ka。从古代欧亚大陆北部到所有美洲原住民的基因流动发生在25-20 ka之间，而古代Beringians在22-18.1 ka之间分支。我们的研究结果支持美洲原住民祖先的长期遗传结构，与Beringian“静止模型”一致（9）。我们表明，基底北方和南部美洲原住民分支，所有其他美洲原住民属于，分歧约17.5-14.6 ka，这可能发生在北美冰盖南部。我们还发现，在11.5 ka之后，一些北方美洲原住民群体接受了来自西伯利亚人群的基因流，该人群与科里亚克人关系最密切，但不是古爱斯基摩人（1）、因纽特人或凯特人（10），美洲原住民基因流入因纽特人是通过北方而不是南方美洲原住民群体（1）。我们的研究结果进一步表明，北方美洲原住民的远北方存在是从一个回迁移，取代或吸收了古代Beringians最初的创始人口。
Despite broad agreement that the Americas were initially populated via Beringia, the land bridge that connected far northeast Asia with northwestern North America during the Pleistocene epoch, when and how the peopling of the Americas occurred remains unresolved(1-5). Analyses of human remains from Late Pleistocene Alaska are important to resolving the timing and dispersal of these populations. The remains of two infants were recovered at Upward Sun River (USR), and have been dated to around 11.5 thousand years ago (ka)(6). Here, by sequencing the USR1 genome to an average coverage of approximately 17 times, we show that USR1 is most closely related to Native Americans, but falls basal to all previously sequenced contemporary and ancient Native Americans(1,7,8). As such, USR1 represents a distinct Ancient Beringian population. Using demographic modelling, we infer that the Ancient Beringian population and ancestors of other Native Americans descended from a single founding population that initially split from East Asians around 36 +/- 1.5 ka, with gene flow persisting until around 25 +/- 1.1 ka. Gene flow from ancient north Eurasians into all Native Americans took place 25-20 ka, with Ancient Beringians branching off around 22-18.1 ka. Our findings support a long-term genetic structure in ancestral Native Americans, consistent with the Beringian 'standstill model'(9). We show that the basal northern and southern Native American branches, to which all other Native Americans belong, diverged around 17.5-14.6 ka, and that this probably occurred south of the North American ice sheets. We also show that after 11.5 ka, some of the northern Native American populations received gene flow from a Siberian population most closely related to Koryaks, but not Palaeo-Eskimos(1), Inuits or Kets(10), and that Native American gene flow into Inuits was through northern and not southern Native American groups(1). Our findings further suggest that the far-northern North American presence of northern Native Americans is from a back migration that replaced or absorbed the initial founding population of Ancient Beringians.