24小时热门版块排行榜    

查看: 81  |  回复: 0
当前主题已经存档。

zzq122zzq

木虫 (正式写手)

[交流] Unexpected origin of an early Eskimo

But hair sample could have been from a wandering mercenary.

Daniel Cressey


This hair sample suggests the earliest Eskimos could have come from an unlikely place.Bjarne GrønnowAn early wave of migration into the New World and the Arctic has been identified by sequencing a genome from a frozen hair excavated in Greenland.

Archaeological evidence shows that there were two waves of migration to Greenland starting 4,500 years ago, first with the Saqqaq and then the Dorset groups, collectively known as the Paleo-Eskimos.

Later, around 1,000 years ago, came the Thule culture which led to the current native population. The relationship between these three groups has been uncertain.

Some theories hold that Paleo-Eskimos derived from the populations that also led to Native Americans, says Eske Willerslev, of the University of Copenhagen’s Centre for Ancient Genetics. Others argue that, like modern Neo-Eskimo populations, they came from Beringia, the land where the Bering Strait now exists.

All in the hair
Attempting to solve this question, Willerslev and his colleagues sequenced the mitochondrial genome of a Paleo-Eskimo using frozen hair recovered from permafrost at an early Saqqaq settlement at Disko Bay in western Greenland, believed to be between 3,400 and 4,500 years old.


A knife found at the excavation site in Greenland.Bjarne GrønnowThe sample matched with neither Native Americans nor Neo-Eskimos, the team reports in Science 1. Instead, it was a good match for a group of mitochondrial haplotypes called D2a1. These haplotypes, themselves groups of genetic variations called alleles, are used by researchers to trace the heritage of modern humans.

Different genetic codes are linked to different regions and groups. D2a1 is linked to Alaska's modern Aleutian Islanders and Siberian Yuit peoples, says Willerslev. “This means there has been migration into the New World that hadn’t been known before.”

It seems that the first migrations into what is now northern Canada and then on to Greenland may not have come from the Native Americans who were already in the Americas, nor from those who later became the Neo-Eskimos.

The whole picture

“What we can show by this data is that Paleo-Eskimos derive from a different group of people than other Native Americans.”
Toomas Kivisild
University of Cambridge
The discovery “clarifies the issue about the peopling of Greenland and northern Canada", says fellow author Toomas Kivisild, of the Leverhulme Centre for Human Evolutionary Studies at the University of Cambridge, UK. “What we can show by this data is that Paleo-Eskimos derive from a different group of people than other Native Americans. This is a positive and conclusive result.”

The work does not shed light on the relationship between the Saqqaq and the Dorset cultures, however. Previously studied Dorset remains have only been identified as being in haplogroup D. Whether they are D3, like some of the Neo-Eskimo groups, or D2a1 is yet to be established, the researchers note.

As the work is based on only a single hair sample, it might not be a true representative of the Saqqaq people. The hair might have belonged to an Aleutian sword-for-hire who tagged along with the migration for money before meeting a chilly end.

ADVERTISEMENT

Three further hair samples from the same site exist and the researchers hope these will yield more information.

“We are still far away from getting the whole picture,” says Willerslev. “This single sample does definitely suggest migration from the Aleutians into the New World.”

References
Gilbert, M. T. P. et al. Science advance online publication (29 May 2008).
回复此楼
已阅   回复此楼   关注TA 给TA发消息 送TA红花 TA的回帖
相关版块跳转 我要订阅楼主 zzq122zzq 的主题更新
普通表情 高级回复(可上传附件)
信息提示
请填处理意见