Researchers Find Link to Nerve Disease in Ancient DNA

Researchers Find Link to Nerve Disease in Ancient DNA

研究人员在古代DNA中发现了神经疾病的关联

【听力音频】

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　　By Mario Ritter, Jr

　　18 January 2024

　　Genetic 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 genes 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 remains 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 grasslands of what is now Ukraine and Russia into northwestern Europe. However, the researchers say those people carried gene 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 variants 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 wagons and herded 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 Oxford University, questioned why a gene variant that seems to have strengthened immunity 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.

　　I'm Mario Ritter, Jr.

　　Lauran Neergaard reported this story for the Associated Press. Mario Ritter, Jr. adapted it for VOA Learning English.

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　　作者：Mario Ritter, Jr

　　2024年1月18日

　　英国剑桥大学的遗传学研究人员表示，古代DNA显示了为何北欧人比其他欧洲人更有可能患上一种神经疾病。

　　这种疾病被称为多发性硬化症或MS。研究人员表示，这种风险源于大约5000年前进入北欧的骑马放牧的牧民的基因。

　　这些发现来自于一个大型项目，该项目比较现代DNA和从人类遗骸（包括牙齿和骨头）中提取的古代遗传物质。

　　去年发布的一项研究称，它在被称为亚美尼亚人的人群中发现了最早的骑马证据。科学家们说，他们生活在4500到5000年前的人类历史的青铜时代。

　　亚美尼亚人从现在的乌克兰和俄罗斯的草原迁移到了西北欧。然而，研究人员说，这些人携带的基因版本在今天被认为会增加一个人患多发性硬化症的风险。

　　研究人员补充说，他们相信同样的基因保护了这些牧民免受他们的牛和羊的感染。

　　这项研究发表在科学出版物《自然》上。

　　威廉·巴里是剑桥的一位遗传学研究者。他帮助撰写了这项研究。他说，所有参与的人都感到惊讶。他说：“这些变种给这些人带来了某种优势。”

　　这个发现得益于一个基因库，其中包含了数千个欧洲和西亚早期人类的样本。这个项目由剑桥大学和丹麦哥本哈根大学的Eske Willerslev领导。

　　虽然MS可以影响任何人群，但在北欧白人后裔中最常见。科学家们一直无法解释为什么。

　　这种疾病的原因尚不清楚。然而，有一种理论认为，感染可能会在具有某些遗传特质的人中引发这种疾病。科学家们说，他们已经发现了230种可能增加MS风险的遗传变异。

　　研究人员研究了大约1600个古代欧亚人的DNA。他们利用这些信息制定了北欧人口移动的地图。他们说，大约5000年前，来自中东的农民开始挤走狩猎采集者。然后亚美尼亚人移居过来。他们骑着马，驾着马车，放牧牛羊。

　　研究团队将古代DNA与存储在英国生物银行的40万现代人的遗传信息进行了比较。他们想看看与MS相关的遗传变异是否在北部持续存在。这是亚美尼亚人移居的欧洲部分，而不是南欧。

　　在现在的丹麦，亚美尼亚人取代了古代农民，使他们成为现代丹麦人的最近祖先，Willerslev说。

　　在被称为斯堪的纳维亚的欧洲北部，MS的发病率特别高。

　　这些发现引发了更多的问题，并表明需要进行更多的研究。研究的一位作者，牛津大学的Astrid Iverson质疑为什么一个看似增强了免疫力的基因变异后来在引发被认为是自身免疫性疾病的过程中发挥了作用。她说，现代人接触动物病菌的方式的差异可能会使免疫系统失衡。

　　我是Mario Ritter, Jr.

　　Lauran Neergaard为美联社报道了这个故事。Mario Ritter, Jr.为VOA学习英语改编了它。

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　　本故事中的词汇

　　herder –n. 照看和照顾像牛羊这样大群生活的动物的人

　　variant –n. 有小差异的某物的版本

　　advantage –n. 使成功更有可能的东西

　　immunity –n. 抵抗疾病的能力

　　autoimmune disease –n. 一种病症，其中身体对感染的防御攻击身体自身产生的物质