英语科普：人类与狗的关系可追溯至2.7万年前

Dogs' special relationship to humans may go back 27,000 to 40,000 years, according to genomic analysis of an ancient Taimyr wolf bone reported in the Cell Press journal Current Biology on May 21. Earlier genome-based estimates have suggested that the

ancestors of modern-day dogs diverged1 from wolves no more than 16,000 years ago, after the last Ice Age. The genome from this ancient specimen2, which has been radiocarbon dated to 35,000 years ago, reveals that the Taimyr wolf represents the most recent common ancestor of modern wolves and dogs.

"Dogs may have been domesticated3 much earlier than is generally believed," says Love Dalén of the Swedish Museum of Natural History. "The only other explanation is that there was a major divergence4 between two wolf populations at that time, and one of these populations subsequently gave rise to all modern wolves." Dalén considers this second explanation less likely, since it would require that the second wolf population subsequently became extinct in the wild.

"It is [still] possible that a population of wolves remained relatively5 untamed but tracked human groups to a large degree, for a long time," adds first author of the study Pontus Skoglund of Harvard Medical School and the Broad Institute.

The researchers made these discoveries based on a small piece of bone picked up during an expedition to the Taimyr Peninsula in Siberia. Initially6, they didn't realize the bone fragment came from a wolf at all; this was only determined7 using a genetic8 test back in the laboratory. But wolves are common on the Taimyr Peninsula, and the bone could have easily belonged to a modern-day wolf. On a hunch9, the researchers decided10 to radiocarbon date the bone anyway. It was only then that they realized what they had: a 35,000-year-old bone from an ancient Taimyr wolf.

The DNA11 evidence also shows that modern-day Siberian Huskies and Greenland sled dogs share an unusually large number of genes12 with the ancient Taimyr wolf.

"The power of DNA can provide direct evidence that a Siberian Husky you see walking down the street shares ancestry13 with a wolf that roamed Northern Siberia 35,000 years ago," Skoglund says. To put that in perspective, "this wolf lived just a few thousand years after Neandertals disappeared from Europe and modern humans started populating Europe and Asia."

词汇解析表：

1 diverged

分开( diverge的过去式和过去分词 )；偏离；分歧；分道扬镳

参考例句：

Who knows when we'll meet again? 不知几时咱们能再见面！

At what time do you get up? 你几时起床？

2 specimen

n.样本，标本

参考例句：

You'll need tweezers to hold up the specimen.你要用镊子来夹这标本。

This specimen is richly variegated in colour.这件标本上有很多颜色。

3 domesticated

adj.喜欢家庭生活的；（指动物）被驯养了的v.驯化( domesticate的过去式和过去分词 )

参考例句：

He is thoroughly domesticated and cooks a delicious chicken casserole. 他精于家务，烹制的砂锅炖小鸡非常可口。来自《简明英汉词典》

The donkey is a domesticated form of the African wild ass. 驴是非洲野驴的一种已驯化的品种。来自《简明英汉词典》

4 divergence

n.分歧，岔开

参考例句：

There is no sure cure for this transatlantic divergence.没有什么灵丹妙药可以消除大西洋两岸的分歧。

In short,it was an age full of conflicts and divergence of values.总之，这一时期是矛盾与价值观分歧的时期。

5 relatively

adv.比较...地，相对地

参考例句：

The rabbit is a relatively recent introduction in Australia.兔子是相对较新引入澳大利

亚的物种。

The operation was relatively painless.手术相对来说不痛。

6 initially

adv.最初，开始

参考例句：

The ban was initially opposed by the US.这一禁令首先遭到美国的反对。

Feathers initially developed from insect scales.羽毛最初由昆虫的翅瓣演化而来。

7 determined

adj.坚定的；有决心的

参考例句：

I have determined on going to Tibet after graduation.我已决定毕业后去西藏。

He determined to view the rooms behind the office.他决定查看一下办公室后面的房间。

8 genetic

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。

9 hunch

n.预感，直觉

参考例句：

I have a hunch that he didn't really want to go.我有这么一种感觉，他并不真正想去。

I had a hunch that Susan and I would work well together.我有预感和苏珊共事会很融洽。

10 decided

adj.决定了的，坚决的；明显的，明确的

参考例句：

This gave them a decided advantage over their opponents.这使他们比对手具有明显的优势。

There is a decided difference between British and Chinese way of greeting.英国人和中国人打招呼的方式有很明显的区别。

11 DNA

(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。

12 genes

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

13 ancestry

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。

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