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DNA shows our history
作者:21ST    来源:高中版第173期    日期: 2010-09-07

外研版高三年级:DNA—the Secret of life

关键词:Personal physical features

话题归类:科技知识Popular science


BELIEVE it or not, your great-great-great-grandfather might have come from Africa!

New DNA studies show that all humans came from an African ancestor who lived only 60,000 years ago. Now researchers are aiming to learn more about how the Earth was populated, by collecting and analyzing genetic samples (基因样本) from 100,000 people around the globe.

The start of the five-year "Genographic (基因地图) Project", was announced last week. It will use advanced laboratory and computer analysis of DNA to figure out how people moved from one part of the world to another. It is sponsored by National Geographic and IBM.

Scientists in the United States, China, Brazil, France, Lebanon, South Africa, United Kingdom, Russia, India and Australia will take part.

"The importance of the work is that we are all, in effect, cousins, separated by a few generations,'' said Spencer Wells, the project director.

If we are all "cousins", why are we so far apart, with different colours and features?

Some parts of the DNA chain remain the same through the generations. These changes happen only occasionally (偶尔的) and leave "genetic markers". These markers allow gene experts like Wells to trace how we become who we are.

"The greatest history book ever written," Wells says, "is the one hidden in our DNA."

Different populations carry distinct (明显的) genetic markers. Our genes allow us to make a map of how ancient humans moved from Africa across the world. Through one path, we can see living evidence of an ancient African trek (艰辛的路程), through India, to populate even faraway Australia.

But to fully complete the picture, geneticists need more samples.

Fudan University in Shanghai is the project's China centre.

"It is very important for China to be part of the research," said Professor Jin Li, from Fudan University, who leads the programme in China. "The results will help us understand more about ourselves and our culture."

He said about 15,000 samples will be collected in China but it has not been decided where to do the research yet.

Some social groups doubt whether it is right to collect such gene samples. Researchers say all the information will be kept secret and not used for any medical or commercial purpose.

To find out more about the project, check out http://www.nationalgeographic.com/genographic/.

Test yourself

1. What is not true about "genetic markers"?

A. They are changes in DNA.

B. They help experts to make a map of humans' migration

C. They have something to do with our skin colour and other features.

D. Different populations have different genetic markers.

2. Which of the following countries won't take part in the project?

A. France

B. Austria

C. the United Kingdom

D. Russia

3. It is important for China to be part of the research because ________.

A. 15,000 Chinese will get the chance to travel to Africa

B. some social groups are against the project outside China

C. It will help us to better understand ourselves

Key: A B C

populate vt. 居住于
sponsor v. 发起,赞助
in effect 事实上,实际上;有效
feature n. 特征,特色
trace v. 追溯,探索
purpose n. 目的,用途

关键词:外研版 高三 DNA—the Secret of life 科技知识Popular science


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