PNAS:早期美洲人的线粒体遗传学

美国犹他大学人类学系对来自美国阿拉斯加的一个双婴儿埋葬地的线粒体DNA的一项研究发现，这两名婴儿来自不同的母系世系，它们在现代北美人群中都是罕见的。一个模型描述了美洲的人类殖民，即一个来自亚洲的人群跨过了白令陆桥，并且经历了长期的隔离，在对该大陆的其余部分殖民之前分化成了不同的遗传人群。Justin C. Tackney及其同事使用下一代测序技术测定了在大约11,500年前埋葬在阿拉斯加Upward Sun河地点的两名婴儿的全线粒体基因组。由于线粒体DNA保存了母系世系，这组作者能够识别出一个婴儿是C1b世系的成员，而另一个婴儿是B2世系的成员。这两个世系在该地区的当代人群中罕见，这提示早期白令陆桥人群的线粒体多样性比现代人群更大。这组作者说，这些结果为称为白令陆桥停滞模型的北美人群遗传学模型提示了证据，该模型描述了伴随着对该大陆殖民的遗传多样性。

原文链接：

Two contemporaneous mitogenomes from terminal Pleistocene burials in eastern Beringia

原文摘要：

Pleistocene residential sites with multiple contemporaneous human burials are extremely rare in the Americas. We report mitochondrial genomic variation in the first multiple mitochondrial genomes from a single prehistoric population: two infant burials (USR1 and USR2) from a common interment at the Upward Sun River Site in central Alaska dating to ∼11,500 cal B.P. Using a targeted capture method and next-generation sequencing, we determined that the USR1 infant possessed variants that define mitochondrial lineage C1b, whereas the USR2 genome falls at the root of lineage B2, allowing us to refine younger coalescence age estimates for these two clades. C1b and B2 are rare to absent in modern populations of northern North America. Documentation of these lineages at this location in the Late Pleistocene provides evidence for the extent of mitochondrial diversity in early Beringian populations, which supports the expectations of the Beringian Standstill Model.

doi: 10.1073/PNAS.1511903112

作者：Justin C. Tackney