VOA慢速英语2009-Agriculture Report - Cow Genome Could Improve Mi

This is the VOA Special English Agriculture Report.
　
Dominette, a Hereford cow whose genetic¹ material was used in the study

Researchers from twenty-five countries have made a genetic map of a cow. Better understanding of what makes a cow a cow could lead to better milk and meat production. It could also help the drug industry.

The Bovine² Genome Sequencing Project found that the cow genome contains at least twenty-two thousand genes³. Most of these are shared among humans as well as mice, rats and other mammals used for comparison.

Mice and rats are commonly used to test new medicines. But the study shows that cows are more similar to humans than to mice or rats.

Project scientist Harris Lewin from the University of Illinois at Urbana-Champaign predicts there will be more laboratory cows in the future. He says during evolution millions of years ago, domesticated⁵ cattle separated from a common ancestor that led to humans.

The new findings are in the journal Science. More than three hundred researchers studied a female Hereford cow from the American state of Montana. The genetic map, or genome, took six years to complete.

A related report looked at genetic changes in cattle over time. More than two hundred fifty thousand years ago, the bovine family tree divided into two major groups.

Taurine cattle have no hump on their back. They are most commonly found in Europe, Africa and East and West Asia, as well as the Americas. Indicine cattle have a hump and are found in India, South and West Asia and East Africa.

Humans started to domesticate⁴ wild cows about eight to ten thousand years ago. Scientists examined several breeds and say the cattle genome appears to show evidence of this selective reproduction.

Today there are more than eight hundred breeds of cattle raised for different reasons. But some people are concerned that breeding has reduced genetic differences among cattle. This could make it easier for disorders⁶ to affect a large number of animals.

The scientists say the current level of diversity within cattle breeds is at least as great as within humans. And they say the new genome will make it possible to better protect genetic diversity.

Yet there may be more questions to settle about what exactly makes a cow a cow. A team led by Steven Salzberg from the University of Maryland also published a cow genome last month in the journal Genome Biology. That team disagreed on some points with the findings in Science.

And that's the VOA Special English Agriculture Report, written by Jerilyn Watson.

1 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。

2 bovine   

adj.牛的；n.牛

参考例句：

• He threw off his pack and went into the rush-grass andand munching,like some bovine creature.他丢开包袱，爬到灯心草丛里，像牛似的大咬大嚼起来。
• He was a gentle,rather bovine man.他是一位文雅而反应迟钝的人。

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 domesticate   

vt.驯养；使归化，使专注于家务

参考例句：

• Many thousand years ago people learned how to domesticate animals.数千年以前人们就学会了饲养动物。
• If you domesticate this raccoon,it will have trouble living in the wild.如果你驯养这只浣熊，它生活在野外将会有困难。

5 domesticated   

adj.喜欢家庭生活的；（指动物）被驯养了的v.驯化( domesticate的过去式和过去分词 )

参考例句：

• He is thoroughly domesticated and cooks a delicious chicken casserole. 他精于家务，烹制的砂锅炖小鸡非常可口。 来自《简明英汉词典》
• The donkey is a domesticated form of the African wild ass. 驴是非洲野驴的一种已驯化的品种。 来自《简明英汉词典》

6 disorders   

n.混乱( disorder的名词复数 )；凌乱；骚乱；（身心、机能）失调

参考例句：

• Reports of anorexia and other eating disorders are on the increase. 据报告，厌食症和其他饮食方面的功能紊乱发生率正在不断增长。 来自《简明英汉词典》
• The announcement led to violent civil disorders. 这项宣布引起剧烈的骚乱。 来自《简明英汉词典》