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科学美国人60秒 SSS 浅肤色变异出现在独立于欧洲的亚洲

时间:2019-12-10 08:56:06

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(单词翻译)

 

This is Scientific American — 60-Second Science. I'm Christopher Intagliata.

In Latin America, Native Americans, Africans, and Europeans have intermixed for centuries. So, a few years back, researchers sought to learn more about the ancestry1 of more than 7,300 people from Brazil, Chile, Colombia, Mexico and Peru. The volunteers provided DNA2 samples. And they also answered the question: what do you think your background is?

Turns out that what they thought—that is, their predicted ancestry—told a different story than their genes4 did—with skin color a key factor.

"Their predicted ancestry is actually very well correlated with their skin color, but poorly correlated with their actual genetic5 ancestry. So that showed us people are actually trying to predict their whole ancestry by just looking at their skin color, which is a pretty crude thing to do, but that's how the attitude is in Latin America." Kaustubh Adhikari, who studies human genetics at University College London.

In particular, lighter6-skinned volunteers tended to overestimate7 their European ancestry whereas darker-skinned subjects overestimated8 their Native American or African backgrounds.

Now a new study by Adhikari and his colleagues offers a reason for the mismatch. The skin color data and the DNA sequences led the researchers to identify a genetic variant9 for lighter skin that arose in Asia 20- to 30-thousand years ago. That event appears to be independent of the evolution of lighter skin in Europe.

What's it all mean? Well, light skin color in Latin Americans could still reflect European ancestry. But it could also indicate Native American ancestry—by way of the original Asian immigrants carrying the trait who crossed the temporary Beringia land bridge into what's now Alaska and became the first Americans.

The researchers were also able to show that this gene3 variant for lighter skin pigmentation is more prevalent in parts of Asia that do not get much sunlight—indicating a possible way this genetic variant could have been selected for. The new study is in the journal Nature Communications.

Adhikari says the findings could help modify Latin Americans' social views. "We know for example there's a big socioeconomic stratification in Latin America, and that correlates, because of the history of colonization10, to people's European ancestry. And a proxy11 of European ancestry is often taken to be light skin color. So what we are trying to show is that such a blind attitude to social aspects is also wrong genetically12, that there's also big variation of skin color from the native side that such kinds of simplistic attitudes would be ignoring."

A reminder13 that ancestry, like so much else, is more than skin deep.

Thanks for listening for Scientific American — 60-Second Science. I'm Christopher Intagliata.


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1 ancestry BNvzf     
n.祖先,家世
参考例句:
  • Their ancestry settled the land in 1856.他们的祖辈1856年在这块土地上定居下来。
  • He is an American of French ancestry.他是法国血统的美国人。
2 DNA 4u3z1l     
(缩)deoxyribonucleic acid 脱氧核糖核酸
参考例句:
  • DNA is stored in the nucleus of a cell.脱氧核糖核酸储存于细胞的细胞核里。
  • Gene mutations are alterations in the DNA code.基因突变是指DNA密码的改变。
3 gene WgKxx     
n.遗传因子,基因
参考例句:
  • A single gene may have many effects.单一基因可能具有很多种效应。
  • The targeting of gene therapy has been paid close attention.其中基因治疗的靶向性是值得密切关注的问题之一。
4 genes 01914f8eac35d7e14afa065217edd8c0     
n.基因( gene的名词复数 )
参考例句:
  • You have good genes from your parents, so you should live a long time. 你从父母那儿获得优良的基因,所以能够活得很长。 来自《简明英汉词典》
  • Differences will help to reveal the functions of the genes. 它们间的差异将会帮助我们揭开基因多种功能。 来自英汉非文学 - 生命科学 - 生物技术的世纪
5 genetic PgIxp     
adj.遗传的,遗传学的
参考例句:
  • It's very difficult to treat genetic diseases.遗传性疾病治疗起来很困难。
  • Each daughter cell can receive a full complement of the genetic information.每个子细胞可以收到遗传信息的一个完全补偿物。
6 lighter 5pPzPR     
n.打火机,点火器;驳船;v.用驳船运送;light的比较级
参考例句:
  • The portrait was touched up so as to make it lighter.这张画经过润色,色调明朗了一些。
  • The lighter works off the car battery.引燃器利用汽车蓄电池打火。
7 overestimate Nmsz5Y     
v.估计过高,过高评价
参考例句:
  • Don't overestimate seriousness of the problem.别把问题看重了。
  • We overestimate our influence and our nuisance value.我们过高地估计了自己的影响力和破坏作用。
8 overestimated 3ea9652f4f5fa3d13a818524edff9444     
对(数量)估计过高,对…作过高的评价( overestimate的过去式和过去分词 )
参考例句:
  • They overestimated his ability when they promoted him. 他们提拔他的时候高估了他的能力。
  • The Ministry of Finance consistently overestimated its budget deficits. 财政部一贯高估预算赤字。
9 variant GfuzRt     
adj.不同的,变异的;n.变体,异体
参考例句:
  • We give professional suggestions according to variant tanning stages for each customer.我们针对每位顾客不同的日晒阶段,提供强度适合的晒黑建议。
  • In a variant of this approach,the tests are data- driven.这个方法的一个变种,是数据驱动的测试。
10 colonization fa0db2e0e94efd7127e1e573e71196df     
殖民地的开拓,殖民,殖民地化; 移殖
参考例句:
  • Colonization took place during the Habsburg dynasty. 开拓殖民地在哈布斯堡王朝就进行过。
  • These countries took part in the colonization of Africa. 这些国家参与非洲殖民地的开发。
11 proxy yRXxN     
n.代理权,代表权;(对代理人的)委托书;代理人
参考例句:
  • You may appoint a proxy to vote for you.你可以委托他人代你投票。
  • We enclose a form of proxy for use at the Annual General Meeting.我们附上委任年度大会代表的表格。
12 genetically Lgixo     
adv.遗传上
参考例句:
  • All the bees in the colony are genetically related. 同一群体的蜜蜂都有亲缘关系。
  • Genetically modified foods have already arrived on American dinner tables. 经基因改造加工过的食物已端上了美国人的餐桌。 来自英汉非文学 - 生命科学 - 基因与食物
13 reminder WkzzTb     
n.提醒物,纪念品;暗示,提示
参考例句:
  • I have had another reminder from the library.我又收到图书馆的催还单。
  • It always took a final reminder to get her to pay her share of the rent.总是得发给她一份最后催缴通知,她才付应该交的房租。

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