VOA慢速英语--研究表明,只有7%的DNA是现代人类独有的

Study: Just 7 Percent of Our DNA¹ Is Special to Modern Humans

A new study finds that just seven percent of the genome, or all genes², of modern humans is special to that group. It suggests today's humans are extremely similar genetically⁴ to their ancestors from tens of thousands of years ago.

The research appeared in the publication Science Advances.

"That's a pretty small percentage," says Nathan Schaefer, a biologist, or life scientist, at the University of California, and a leader of the research.

"This kind of finding is why scientists are turning away from thinking that we humans are so vastly different from Neanderthals," he said.

The Neanderthal human group died out around 40,000 years ago.

The research used DNA taken from the remains⁵ of Neanderthals and other early human groups called Denisovans. The scientists compared the DNA to that from 279 living people from around the world.

Scientists already knew that modern people share some DNA with Neanderthals, but different people share different parts of that genome. One goal of the new research was to identify the genes that only modern humans have.

John Hawks⁶ is a paleoanthropologist, a scientist that researches human origin and development, at the University of Wisconsin, Madison. He was not involved in the study. He said establishing the genes shared by the groups is mathematically difficult. He praised the researchers for their work. They "developed a valuable tool that takes account of missing data in the ancient genomes," Hawks said.

The research also showed that an even smaller percentage of the modern human genome, 1.5 percent, is singularly shared among humans of today. Those few genes could answer what truly makes modern human beings different.

Richard Green is a biologist at the University of California, Santa Cruz and one of the writers of the paper. He said the genome areas shared only among today's humans are "highly enriched" for genes dealing⁷ with brain development and function.

In 2010, Green helped produce the first outline of a Neanderthal genome. Four years later, geneticist Joshua Akey co-wrote a paper showing that modern humans carry some Neanderthal DNA. Since then, scientists have continued to develop ways to take and study genetic³ material from fossils.

Akey is now at Princeton and was not involved in the new research. But he also praised the study. Better tools, he said, permit scientists to "ask increasingly more detailed⁸ questions about human history and evolution."

Alan Templeton is a geneticist at Washington University, St. Louis. He questioned one of the findings reported by the investigators⁹. The scientists assume, he said, that human genome changes are randomly¹⁰ spread.

Instead, Akey argues the findings show "that we're actually a very young species," said Akey. "Not that long ago, we shared the planet with other human lineages."

Words in This Story

pretty –adv. to a great degree or extent

vast –adj. very great in size, amount, or extent

function –n. the special purpose or activity for which a thing exists or is used

evolution –n. a theory that the differences between modern plants and animals are because of changes that happened by a natural process over a very long time

assume –v. to think that something is true or probably true without knowing that it is true

lineage –n. the people who were in someone's family in past times

1 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。

2 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

3 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。

4 genetically   

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

5 remains   

n.剩余物，残留物；遗体，遗迹

参考例句：

• He ate the remains of food hungrily.他狼吞虎咽地吃剩余的食物。
• The remains of the meal were fed to the dog.残羹剩饭喂狗了。

6 hawks   

鹰( hawk的名词复数 )； 鹰派人物，主战派人物

参考例句：

• Two hawks were hover ing overhead. 两只鹰在头顶盘旋。
• Both hawks and doves have expanded their conditions for ending the war. 鹰派和鸽派都充分阐明了各自的停战条件。

7 dealing   

n.经商方法，待人态度

参考例句：

• This store has an excellent reputation for fair dealing.该商店因买卖公道而享有极高的声誉。
• His fair dealing earned our confidence.他的诚实的行为获得我们的信任。

8 detailed   

adj.详细的，详尽的，极注意细节的，完全的

参考例句：

• He had made a detailed study of the terrain.他对地形作了缜密的研究。
• A detailed list of our publications is available on request.我们的出版物有一份详细的目录备索。

9 investigators   

n.调查者，审查者( investigator的名词复数 )

参考例句：

• This memo could be the smoking gun that investigators have been looking for. 这份备忘录可能是调查人员一直在寻找的证据。
• The team consisted of six investigators and two secretaries. 这个团队由六个调查人员和两个秘书组成。 来自《简明英汉词典》

10 randomly   

adv.随便地，未加计划地

参考例句：

• Within the hot gas chamber, molecules are moving randomly in all directions. 在灼热的气体燃烧室内，分子在各个方向上作无规运动。 来自辞典例句
• Transformed cells are loosely attached, rounded and randomly oriented. 转化细胞则不大贴壁、圆缩并呈杂乱分布。 来自辞典例句