VOA科学技术2024--Researchers Find Link to Nerve Disease in Ancient DNA

Researchers Find Link to Nerve Disease in Ancient DNA¹

Genetic³ researchers at the University of Cambridge in Britain say ancient DNA shows why northern Europeans have a higher risk of getting a nerve disease than other Europeans.

The disease is called multiple sclerosis or MS. The researchers said the risk lies in genes⁴ from horse-riding cattle herders who entered northern Europe about 5,000 years ago.

The findings come from a huge project to compare modern DNA with ancient genetic material taken from human remains⁵ including teeth and bones.

A study released last year said it identified the earliest evidence of horse riding in people called the Yamnaya. The scientists say they lived 4,500 to 5,000 years ago during the Bronze Age period of human history.

The Yamnaya moved from the grasslands⁶ of what is now Ukraine and Russia into northwestern Europe. However, the researchers say those people carried gene² versions that today are known to increase a person's risk of multiple sclerosis.

The researchers added that they believe the same genes protected those herders from infections from their cattle and sheep.

The research was published in Nature, a scientific publication.

William Barrie is a genetic researcher at Cambridge. He helped write the study. He said everyone involved was surprised. "These variants⁸ were giving these people an advantage of some kind," he said.

The finding was made possible by a gene bank with thousands of examples of early humans in Europe and western Asia. That project is led by Eske Willerslev of Cambridge and the University of Copenhagen in Denmark.

While MS can strike any population it is most common among white descendants of northern Europeans. Scientists have been unable to explain why.

The cause of the disease is not known. However, one theory is that infections could cause it in people who have certain genetic qualities. Scientists say they have found 230 genetic variants that might increase the risk of MS.

The researchers studied DNA from about 1,600 ancient Eurasians. They used the information to develop of map of population movements in northern Europe. They said farmers from the Middle East began pushing out hunter-gatherers about 5,000 years ago. Then the Yamnaya moved in. They traveled with horses and wagons⁹ and herded¹⁰ cattle and sheep.

The research team compared the ancient DNA to the genetic information of 400,000 modern-day people stored in UK Biobank in Britain. They wanted to see if MS-linked genetic variations persisted in the north. That is the part of Europe where the Yamnaya moved, rather than southern Europe.

In what is now Denmark, the Yamnaya replaced ancient farmers, making them the closest ancestors of modern Danes, Willerslev said.

Rates of MS are especially high in the northern part of Europe known as Scandinavia.

The findings raise additional questions and suggest a need for more research. One of the writers of the study, Astrid Iverson of Oxford¹¹ University, questioned why a gene variant⁷ that seems to have strengthened immunity¹² later plays a part in causing what is believed to be an autoimmune disease. Differences in how modern humans are exposed to animal germs might push the immune system out of balance, she said.

Words in This Story

herder –n. a person who keeps and cares for animals that live in large groups like cattle and sheep

variant –n. a version of something that has a small difference

advantage –n. something that makes success more likely

immunity –n. the ability to resist disease

autoimmune disease –n. a condition in which the body's own defenses against infection attack substances that the body itself creates

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 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。

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 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

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 grasslands   

n.草原，牧场( grassland的名词复数 )

参考例句：

• Songs were heard ringing loud and clear over the grasslands. 草原上扬起清亮激越的歌声。 来自《现代汉英综合大词典》
• Grasslands have been broken and planted to wheat. 草原已经开垦出来，种上了小麦。 来自《简明英汉词典》

7 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。

8 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

9 wagons   

n.四轮的运货马车( wagon的名词复数 )；铁路货车；小手推车

参考例句：

• The wagons were hauled by horses. 那些货车是马拉的。
• They drew their wagons into a laager and set up camp. 他们把马车围成一圈扎起营地。

10 herded   

群集，纠结( herd的过去式和过去分词 )； 放牧； （使）向…移动

参考例句：

• He herded up his goats. 他把山羊赶拢在一起。
• They herded into the corner. 他们往角落里聚集。

11 Oxford   

n.牛津（英国城市）

参考例句：

• At present he has become a Professor of Chemistry at Oxford.他现在已是牛津大学的化学教授了。
• This is where the road to Oxford joins the road to London.这是去牛津的路与去伦敦的路的汇合处。

12 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。