英语听力文摘 English Digest 540、穴居人怎样抵抗疾病？

 　　How Neanderthals Fought Disease

 

　　Every year people are encouraged to get their annual flu shots. Signs are posted at drug stores and clinics. Get your shots here. Modern preventive medicine has saved millions of lives. But you may be surprised to hear that Neanderthals may have helped ancient humans prevent disease. Not with medicine but with immunity¹ genes³.

 

　　Humans have a group of about two hundred genes that keep our immune system running smoothly⁴. These genes allow our bodies to respond to a large number of disease causing agents and adapt to new disease. One of those genes has an allele, HLA C0702, that can be found in many European and Asian people, but not in Africans. Another allele, HLA A11, is found mostly in Asians.

 

　　Both alleles were found in Neanderthal DNA⁵. Scientists studying ancient Neanderthals believe they may know why some modern people have the immunity alleles while others do not. When humans moved out of Africa one hundred thousand years ago, their immune systems were adapted to fight African diseases. Neanderthals on the other hand had already been living in Europe and Asia for thousands of years. They had been exposed to different diseases, and different alleles had evolved to combat them.

 

　　Scientists already know that the modern human genome is somewhere between one and four percent Neanderthal in origin. It is not a far leap to speculate that inbreeding may have resulted in shared immunity genes, too. More research is needed to determine if the gene² alleles came from a common ancestor, or directly from Neanderthals. In either case, the story of inheriting disease resistance is important in understanding modern man’s survival and migration⁶ around the world.

1 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。

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 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 smoothly   

adv.平滑地，顺利地，流利地，流畅地

参考例句：

• The workmen are very cooperative,so the work goes on smoothly.工人们十分合作，所以工作进展顺利。
• Just change one or two words and the sentence will read smoothly.这句话只要动一两个字就顺了。

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 migration   

n.迁移，移居，（鸟类等的）迁徙

参考例句：

• Swallows begin their migration south in autumn.燕子在秋季开始向南方迁移。
• He described the vernal migration of birds in detail.他详细地描述了鸟的春季移居。