VOA科学技术2023--Research Shows Genetic Influence of Neanderthals, Denisovans

Research Shows Genetic² Influence of Neanderthals, Denisovans

Neanderthals live on within us.

These ancient human relatives, and others, called Denisovans, once lived alongside our early Homo sapiens ancestors. The groups mixed and had children. As a result, some of the Neanderthals and Denisovans live on in our genes³. And science is starting to show just how much that shapes us.

Mary Prendergast, a Rice University archeologist, said, "We're now carrying the genetic legacies⁴ and learning about what that means for our bodies and our health."

In the past few months, researchers have linked Neanderthal DNA⁵ to a serious hand disease, the shape of people's noses and other human traits. They even placed a gene¹ carried by Neanderthals and Denisovans into mice to investigate its effects on biology. The researchers found that the gene gave the mice larger heads and an extra rib⁶.

Much of the human story remains⁷ a mystery. But Dr. Hugo Zeberg of the Karolinska Institute in Sweden said new technologies and research are helping⁸ scientists begin to answer the questions: "Who are we? Where did we come from?"

And the answers point to a deep reality: We have far more in common with our ancient cousins than we ever thought.

Neanderthal, Denisovan DNA

Until recently, the genetic legacy⁹ from ancient humans was invisible. But there has been a number of discoveries from ancient DNA, an area of study developed by Nobel Prize winner Svante Paabo. He was first in creating a Neanderthal genome.

Research shows some African populations have almost no Neanderthal DNA, while those from European or Asian backgrounds have up to two percent. Denisovan DNA is rarely found in most parts of the world but makes up four to six percent of the DNA of people in Melanesia. The Pacific Ocean area extends from New Guinea to the Fiji Islands.

That may not sound like much, but it adds up: Even though only 100,000 Neanderthals ever lived, "half of the Neanderthal genome is still around, in small pieces scattered¹¹ around modern humans," said Zeberg, who works closely with Paabo.

It is also enough to affect us in very real ways. Scientists studying the subject say the DNA can be both helpful and harmful.

For example, Neanderthal DNA has been linked to autoimmune diseases like Graves' disease and rheumatoid arthritis¹². When Homo sapiens came out of Africa, they had no immunity¹³ to diseases in Europe and Asia. But, Neanderthals and Denisovans already living there did.

Chris Stringer is a human evolution researcher at the Natural History Museum in London. Stringer said that by mating with Neanderthals and Denisovans, Homo sapiens "got a quick fix to our immune systems, which was good news 50,000 years ago." Stringer added, "The result today is, for some people, that our immune systems are oversensitive, and sometimes they turn on themselves."

In 2020, research by Zeberg and Paabo found that a major genetic risk factor for severe COVID-19 came from Neanderthals. "We compared it to the Neanderthal genome and it was a perfect match," Zeberg said.

The next year, they found a set of DNA variants¹⁵ along a single chromosome¹⁶ inherited from Neanderthals had the opposite effect: protecting people from severe COVID.

Much less is known about our genetic legacy from Denisovans – although some research has linked genes from them to fat processing and better performance at high altitudes. Maanasa Raghavan, a human genetics expert at the University of Chicago, said Tibetans carry an amount of Denisovan DNA. She noted¹⁷ that the population continues to live and do well in low-oxygen environments today.

Human evolution

John Hawks¹⁸ of the University of Wisconsin-Madison said that human evolution was not about "survival of the fittest and extinction¹⁹." Instead, he suggested, it is about "interaction and mixture."

Researchers expect to learn more as the science continues to develop. Even when ancient bones are not available, scientists today can get DNA from soil where ancient humans once lived.

And there are less-explored places in the world where researchers hope to learn more. Zeberg said "biobanks" that collect biological materials will likely be established in more countries.

As researchers go deeper into humanity's genetic legacy, scientists expect to find even more evidence of how much we mixed with our ancient cousins and all they left us.

"Perhaps," Zeberg said, "we should not see them as so different."

Words in This Story

legacy – n. something that comes from someone in the past

trait – n. a quality that makes one person or thing different from another

genome – n. the complete set of genetic material present in an organism

scatter¹⁰ – v. to cause (things or people) to go in different directions

variant¹⁴ – n. something that is different in some way from others of the same kind

1 gene   

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。

2 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。

3 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

4 legacies   

n.遗产( legacy的名词复数 )；遗留之物；遗留问题；后遗症

参考例句：

• Books are the legacies that a great genius leaves to mankind. 书是伟大的天才留给人类的精神财富。 来自辞典例句
• General legacies are subject to the same principles as demonstrative legacies. 一般的遗赠要与指定数目的遗赠遵循同样的原则。 来自辞典例句

5 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。

6 rib   

n.肋骨，肋状物

参考例句：

• He broke a rib when he fell off his horse.他从马上摔下来折断了一根肋骨。
• He has broken a rib and the doctor has strapped it up.他断了一根肋骨，医生已包扎好了。

7 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。

8 helping   

n.食物的一份&adj.帮助人的，辅助的

参考例句：

• The poor children regularly pony up for a second helping of my hamburger. 那些可怜的孩子们总是要求我把我的汉堡包再给他们一份。
• By doing this, they may at times be helping to restore competition. 这样一来, 他在某些时候,有助于竞争的加强。

9 legacy   

n.遗产，遗赠；先人(或过去)留下的东西

参考例句：

• They are the most precious cultural legacy our forefathers left.它们是我们祖先留下来的最宝贵的文化遗产。
• He thinks the legacy is a gift from the Gods.他认为这笔遗产是天赐之物。

10 scatter   

vt.撒，驱散，散开；散布/播；vi.分散，消散

参考例句：

• You pile everything up and scatter things around.你把东西乱堆乱放。
• Small villages scatter at the foot of the mountain.村庄零零落落地散布在山脚下。

11 scattered   

adj.分散的，稀疏的；散步的；疏疏落落的

参考例句：

• Gathering up his scattered papers,he pushed them into his case.他把散乱的文件收拾起来，塞进文件夹里。

12 arthritis   

n.关节炎

参考例句：

• Rheumatoid arthritis has also been linked with the virus.风湿性关节炎也与这种病毒有关。
• He spent three months in the hospital with acute rheumatic arthritis.他患急性风湿性关节炎，在医院住了三个月。

13 immunity   

n.优惠；免除；豁免，豁免权

参考例句：

• The law gives public schools immunity from taxation.法律免除公立学校的纳税义务。
• He claims diplomatic immunity to avoid being arrested.他要求外交豁免以便避免被捕。

14 variant   

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。

15 variants   

n.变体( variant的名词复数 )；变种；变型；（词等的）变体

参考例句：

• Those variants will be preserved in the'struggle for existence". 这些变异将在“生存竞争”中被保留下来。 来自辞典例句
• Like organisms, viruses have variants, generally called strains. 与其他生物一样，病毒也有变种，一般称之为株系。 来自辞典例句

16 chromosome   

n.染色体

参考例句：

• Chromosome material with exhibits of such behaviour is called heterochromatin.表现这种现象的染色体物质叫做异染色质。
• A segment of the chromosome may become lost,resulting in a deletion.染色体的一个片段可能会丢失，结果产生染色体的缺失。

17 noted   

adj.著名的，知名的

参考例句：

• The local hotel is noted for its good table.当地的那家酒店以餐食精美而著称。
• Jim is noted for arriving late for work.吉姆上班迟到出了名。

18 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。

19 extinction   

n.熄灭，消亡，消灭，灭绝，绝种

参考例句：

• The plant is now in danger of extinction.这种植物现在有绝种的危险。
• The island's way of life is doomed to extinction.这个岛上的生活方式注定要消失。