科学美国人60秒 SSS DNA Points to Multiple Migrations into the Americas（在线收听）

DNA Points to Multiple Migrations into the Americas

美洲多次殖民迁移之谜

For more than ten thousand years, Alaska Native and Canadian First Nations people have lived along the Northwest coast of North America. Now, ancient remains have provided genetic proof of that long habitation.

一万多年间，阿拉斯加原住民和加拿大原住民一直生活在北美洲的西北海岸。现在，远古遗骸为他们长居于此提供了遗传学证据。

 “There’s largely the same gene pool in northern Northwest North America today that there was ten thousand years ago.”

“现在北美西北北部地区的基因库与一万年前的基本相同。”

\Ripan Malhiat the University of Illinois-Champagne. He and colleagues analyzed the DNA in four skeletons found in the region that range from 1,500 to 10,000 years old. And the results have two major implications. First, they support traditional oral histories about life in the region. Second, they open up the possibility for new theories about how people migrated to the continent—namely, more than one colonization.

伊利诺斯州大学香槟分校的Ripan Malhi说道。他和同事们分析了在这一地区发现的四具古遗骸骨骼中的DNA，这些骸骨从1500到10000岁不等。研究结果主要有两个重大含义。首先，他们为传统的关于该地区生活的口述历史提供了支持。第二，他们为关于人们如何迁移到该大陆的新理论开创了可能性——即，不止发生一次殖民地的开拓。

“It could be that folks first moved south into Central and South America and then back up into North America, or it could be that there was another movement from northeast Asia later on in time. So, there are many different possibilities that could explain the patterns that we are seeing.”

“一种可能性是人们首先向南迁移到美国中部和南部，然后又回到北美，也有可能是后来东北亚出现了另一场迁移到此的运动。所以，导致我们现在看到的这种模式出现的原因，有许多不同的可能性可以解释。”

The study is in the Proceedings of the National Academy of Sciences.

这项研究发表在《美国国家科学院院刊》上。

The researchers also compared genetic data from Northwest coast populations with DNA in remains unearthed south of the Canadian border. The analysis shows that the almost 13,000 year old Anzick Child found in Montana is related more closely to people from Central and South America than to Washington state’s 9,000 year old Kennewick Man, who is of entirely different lineage. He is not related to people of the Northwest Coast, and his genes aren’t all that closely linked to Anzick Child’s South American relatives either. Which shows that the story of the settlement of the Western Hemisphere is still very much a work in progress.

研究人员还将西北海岸居民的基因数据与在加拿大边境南部出土遗骸中的基因做了对比。分析显示，在蒙大拿州发现的近13000岁的Anzick男孩与来自中美洲和南美洲的人联系更加紧密——比起在华盛顿州发现的9000岁的肯纳威克人。肯纳威克人拥有完全不同的血统。他与西北海岸的人没有血缘关系，他的基因与Anzick男孩的南美亲戚也没有多么紧密。这表明，西半球的殖民故事仍有许多待解之谜。