听力文摘：穴居人怎样抵抗疾病

How Neanderthals Fought Disease

穴居人怎样抵抗疾病

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.

每年人们都会被鼓励去打流感疫苗。告示会被贴在诊所和药店里：在这儿打疫苗。现代预防医学挽救了数百万人的生命。但是当你听到穴居人可以帮助过去的人预防疾病时，你可能会感到很吃惊，不是利用药物而是通过免疫基因。

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.

人类有一组基因，大约200个，它们让我们的免疫系统正常地运转。这些基因使我们的身体对大量的病源物质做出反应，并且适应新的疾病。这些基因中的一个有 等位基因，HLAC0702，这种基因可以在许多欧洲或者亚洲人身上找到，但无法在非洲人身上找到。另一种等位基因HLA A11则在亚洲人身上最为常见。

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.

这两种等位基因在穴居人的DNA中却都可以找到。研究古穴居人的科学家们相信他们可能知道为什么一些现代人有免疫等位基因，而其他人没有。十万年前，当人 们搬离非洲时，他们的免疫系统就已经适应了同非洲疾病对抗。然而，穴居人在欧洲和亚洲已经生活了数千年。他们被暴露在不同的疾病之下，并且进化出不同的等 位基因同疾病对抗。

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.

科学家们已经知道现代人类基因组在某种程度上1%到4%是起源于穴居人。不难推测，近亲繁殖也许是造成免疫基因共享的原因。但我们还需要更多的研究来确定 是否等位基因来自于人类共同的祖先，还是直接来自于穴居人。在任何一个情况下，遗传抗病性在理解现代人生存和在全世界范围内迁徙都是十分重要的。

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。