bbc_me_virus_cn-MediaEnglish媒体英语27April2012.PDFVIP

Media English 体英语 27 April 2012 請注意：中文文字内容只提供簡體版 Ancient viruses 恐龙时期的病毒 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。BBC 记者David Shukman 发回了以下报道。 With only a small part of our genetic material fully understood, scientists have been trying to unravel where most of our DNA came from and what it does. Now researchers from Oxford, New York and Belgium have investigated the genes of 38 mammals – including humans, mice, elephants and dolphins, and theyve 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 legacy 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 parasites might play. Theres 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 survivors from the distant past may provide clues to the early detection of cancers or infections. Questions 1. How many mammals did the researchers study in their investigation? 2. How long ago do the scientists think at least one of the viruses infected our ancestors? 3. Which two words are used in the report to mean a virus? 4. Are these ancient viruses harmful to people? Media English 体英语 © British Broadcasting Corporation 2012 Page 1 of 3 /learningenglish Glossary 词汇