英语听力精选进阶版 7248

一项研究结果显示，远在恐龙时代出现的一些病毒仍然在活跃于当代人类的遗传基因里。

至今为止，科学界对基因组的了解仍然处于初级状态，科学家们希望这项研究能够提供有关人类基因渊源的线索。

With only a small part of our genetic¹ material fully² understood, scientists have been trying to unravel³ where most of our DNA⁴ came from and what it does. Now researchers from Oxford⁵, New York and Belgium have investigated the genes⁶ of 38 mammals – including humans, mice, elephants and dolphins, and they've found that most of them share traces of the same ancient viruses. The work has established that at least one virus infected our common ancestors as long as one hundred million years ago.

The scientists found that these micro-organisms have adapted to stay within their host cell where they have thrived. So within the double helix of our DNA lies not only a legacy⁷ of past infections but also a miniature eco-system in which the viruses live on and evolve.

The researchers hope that further work will identify what role these genetic parasites⁹ might play. There's no evidence that they cause harm, indeed one ancient virus is known to help in the growth of the placenta. According to the senior author of the study, Dr Robert Belshaw of Oxford University, understanding these survivors¹⁰ from the distant past may provide clues to the early detection of cancers or infections.

Quiz 听力测试

How many mammals did the researchers study in their investigation¹¹?

38 species, including humans, mice, elephants and dolphins.

How long ago do the scientists think at least one of the viruses infected our ancestors?

100 million years ago.

Which two words are used in the report to mean a virus?

A parasite⁸ and a micro-organism.

Are these ancient viruses harmful to people today?

No. There's no evidence of them being harmful to people.

Glossary 词汇表

to unravel 解开

genes 基因

traces 微量的

to establish 确认

micro-organism 微生物

to thrive 繁荣兴旺

legacy 遗留下来的资产

parasites 寄生虫

placenta 胎盘

to provide clues 提供线索

1 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。

2 fully   

adv.完全地，全部地，彻底地；充分地

参考例句：

• The doctor asked me to breathe in,then to breathe out fully.医生让我先吸气，然后全部呼出。
• They soon became fully integrated into the local community.他们很快就完全融入了当地人的圈子。

3 unravel   

v.弄清楚（秘密）；拆开，解开，松开

参考例句：

• He was good with his hands and could unravel a knot or untangle yarn that others wouldn't even attempt.他的手很灵巧，其他人甚至都不敢尝试的一些难解的绳结或缠在一起的纱线，他都能解开。
• This is the attitude that led him to unravel a mystery that long puzzled Chinese historians.正是这种态度使他解决了长期以来使中国历史学家们大惑不解的谜。

4 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。

5 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。

6 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

7 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。

8 parasite   

n.寄生虫；寄生菌；食客

参考例句：

• The lazy man was a parasite on his family.那懒汉是家里的寄生虫。
• I don't want to be a parasite.I must earn my own way in life.我不想做寄生虫，我要自己养活自己。

9 parasites   

寄生物( parasite的名词复数 )； 靠他人为生的人； 诸虫

参考例句：

• These symptoms may be referable to virus infection rather than parasites. 这些症状也许是由病毒感染引起的，而与寄生虫无关。
• Kangaroos harbor a vast range of parasites. 袋鼠身上有各种各样的寄生虫。

10 survivors   

幸存者，残存者，生还者( survivor的名词复数 )

参考例句：

• The survivors were adrift in a lifeboat for six days. 幸存者在救生艇上漂流了六天。
• survivors clinging to a raft 紧紧抓住救生筏的幸存者

11 investigation   

n.调查，调查研究

参考例句：

• In an investigation,a new fact became known, which told against him.在调查中新发现了一件对他不利的事实。
• He drew the conclusion by building on his own investigation.他根据自己的调查研究作出结论。