VOA慢速英语2014 我们来自哪里?

 

Where Do We Come From? 我们来自哪里?

Would you like to know where your ancestors came from? British and American scientists may have found answers for you. They have developed a new algorithm to study deoxyribonucleic acid, also known as DNA¹ -- the building blocks of life.

The algorithm is a step-by-step operation for solving problems. It is called “Geographic Population Structure,” or GPS. The report was prepared by researchers from the University of Sheffield in England, and the University of Southern California. It was published in the journal Nature Communications.

The researchers say GPS can find a village or tribe where genes² became mixed as far back as 1,000 years ago, during population movements or invasions. At such times, people from groups that were separated earlier came together and had children.

The British and American scientists tested their algorithm by studying genetic³ information from 200 individuals. The people were from 10 villages on the Italian island of Sardinia. GPS correctly placed 25 percent of the people directly in their villages. Most of the other individuals were placed within 50 kilometers of their villages. A test involving more than 20 islands in the Pacific Ocean produced similar results. In all, 98 percent of the information proved correct.

The scientists say the new method may be important not only for learning about ancestors, but also for health reasons. They say that knowing one’s genetic code may show what conditions and sicknesses may be likely to affect a person.

But valuable as it may prove to be, there are more-traditional ways that people can learn about their ancestry⁴. Some families pass information about family history to the next generation. In turn, those children pass the information on to their children.

And some people have their DNA studied through what is called bio-geographical sequencing. This method places people correctly within about 700 kilometers in Europe. But the rate of success is much lower in other parts of the world.

1 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。

2 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

3 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。

4 ancestry   

n.祖先，家世

参考例句：

• Their ancestry settled the land in 1856.他们的祖辈1856年在这块土地上定居下来。
• He is an American of French ancestry.他是法国血统的美国人。