练习 | 科学美国人:DNA显示人类多次向美洲迁移

练习 | 科学美国人:DNA显示人类多次向美洲迁移

2.1分钟 1750 120wpm

DNA显示人类多次向美洲迁移

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科学美国人60秒:DNA显示人类多次向美洲迁移
燕山大学 刘立军 宋葳 编写


◆TRANSCRIPT

This is Scientific American - 60-Second Science. I'm Emily Schwing.
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.

"There's largely the same gene pool in northern northwest North America today that there was ten thousand years ago."

Ripan Malhi at the University of Illinois-Champaign. 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.

"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 into North America later on in time. So, there are many different possibilities that could explain the patterns that we are seeing."

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

Thanks for listening the Scientific American - 60-Second Science. I'm Emily Schwing.


Adapted from 人类多次向美洲迁移

◆VOCABULARY

1.habitation n.(不可数名词)the act of living in a place居住。例如:
○They looked around for any signs of habitation.他们四处寻找有人居住的迹象。
○The houses were unfit for human habitation (= not clean or safe enough for people to live in) .
那些房子不适合人居住。

2. skeleton n. the structure of bones that supports the body of a person or an animal; a model of this struture骨骼;骨架;骨骼标本。例如:
○The human skeleton consists of 206 bones.人的骨骼由206块骨头组成。
○a dinosaur skeleton恐龙骨架

3.colonization n. 殖民

4.unearth v.to find sth. in the ground by digging 挖掘;发掘;使出土。例如:to unearth buried treasures挖掘地下埋藏的珍宝

5.lineage n.(不可数名词,可数名词)(fromal) the series of families that sb. comes from originally 世系;宗系;家系;血统

◆QUESTIONS
Read the statements. Then listen to the news and check (√) the true or (×) false statements.


1. For more than ten thousand years, Alaska Native and Canadian First Nations people have lived along the Northeast?coast of North America.

2. Ancient remains have provided genetic proof of that long habitation.

3. Ripan Malhi and his colleagues analyzed the DNA in four skeletons found in the region that range from 1,500 to 10,000 years old, and their?results have?three?major implications.

4. Ripan Malhi and his colleagues open up the possibility for new theories about how people migrated to the continent.

5. The researchers also compared genetic data from Northwest coast populations with DNA in remains unearthed south of the Canadian border.

◆KEY

×1. For more than ten thousand years, Alaska Native and Canadian First Nations people have lived along the Northeast coast of North America. 正确表达:For more than ten thousand years, Alaska Native and Canadian First Nations people have lived along the Northwest coast of North America.

√2. Ancient remains have provided genetic proof of that long habitation.

× 3. Ripan Malhi and his colleagues analyzed the DNA in four skeletons found in the region that range from 1,500 to 10,000 years old, and their results have three major implications.?正确表达:Ripan Malhi and his colleagues analyzed the DNA in four skeletons found in the region that range from 1,500 to 10,000 years old, and their results have two major implications.

√4. Ripan Malhi and his colleagues open up the possibility for new theories about how people migrated to the continent.

√5. The researchers also compared genetic data from Northwest coast populations with DNA in remains unearthed south of the Canadian border.

  • 时长:2.1分钟
  • 语速:120wpm
  • 来源:刘立军、宋葳 2017-11-27