VOA慢速英语2010年-Agriculture Report_ Mapping the Way to

This is the VOA Special English Agriculture Report.

Soybeans are eaten by people and fed to animals. Some farmers grow them to replace lost nitrogen in the soil.

Soybeans were first grown in Asia thousands of years ago. Now scientists have a full genetic² map of the soybean. This is the first genome completed for a member of the legume family.

The genome will make it easier to target different qualities and develop improved crops. Sequencing the genes³, organizing all of them in order, will save many hours of searching. It will make it easier to search for what each gene¹ is responsible for.

A report on the genome appeared last week in the journal Nature.

Scott Jackson at Purdue University in West Lafayette, Indiana, helped lead the study team. He says the kind of soybeans they studied have forty-six thousand genes. Between seventy and eighty percent of them, however, are copies of other genes.

Some genes change or disappear over time. But Professor Jackson explains that soybeans have kept copies of most their genes. This is fairly unusual for plants, he says, and extremely unusual for animals.

Genes are organized along chromosomes⁴. These contain molecules⁵ of DNA⁶, the building blocks of life.

The researchers found that the sets of chromosomes in soybeans have copied themselves at least twice. It happened almost sixty million years ago and again thirteen million years ago.

Over time, genes develop changes, known as mutations. Scientists can tell when these changes happened. The number of mutations over time helped the team estimate when the duplications in soybeans took place.

The genome could help genetic engineers develop soybeans that are processed better by farm animals. Soybeans contain chemicals called phytates. These prevent the absorption of phosphorus in the diet.

Pigs and chickens especially are affected⁷. Undigested phosphorus in their waste can pollute water supplies.

Genetic engineering has already reduced phytates in soybeans. Now with the gene map there could be further reductions.

The genome could also help farmers avoid Asian soybean rust⁸ disease, a highly destructive fungus⁹ spread by the wind. The researchers say they found a gene for resistance to this disease. Now they have to find a way to use it.

And that's the VOA Special English Agriculture Report, written by Jerilyn Watson. You can find transcripts¹⁰, MP3s and captioned¹¹ videos of our reports at voaspecialenglish.com. I'm Bob Doughty¹².

1 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。

2 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。

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 chromosomes   

n.染色体( chromosome的名词复数 )

参考例句：

• Chromosomes also determine the sex of animals. 染色体也决定动物的性别。 来自《简明英汉词典》
• Each of four chromosomes divide longitudinally. 四种染色体的每一种都沿着纵向分裂。 来自《现代汉英综合大词典》

5 molecules   

分子( molecule的名词复数 )

参考例句：

• The structure of molecules can be seen under an electron microscope. 分子的结构可在电子显微镜下观察到。
• Inside the reactor the large molecules are cracked into smaller molecules. 在反应堆里，大分子裂变为小分子。

6 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。

7 affected   

adj.不自然的，假装的

参考例句：

• She showed an affected interest in our subject.她假装对我们的课题感到兴趣。
• His manners are affected.他的态度不自然。

8 rust   

n.锈；v.生锈；(脑子)衰退

参考例句：

• She scraped the rust off the kitchen knife.她擦掉了菜刀上的锈。
• The rain will rust the iron roof.雨水会使铁皮屋顶生锈。

9 fungus   

n.真菌，真菌类植物

参考例句：

• Mushrooms are a type of fungus.蘑菇是一种真菌。
• This fungus can just be detected by the unaided eye.这种真菌只用肉眼就能检查出。

10 transcripts   

n.抄本（ transcript的名词复数 ）；转写本；文字本；副本

参考例句：

• Like mRNA, both tRNA and rRNA are transcripts of chromosomal DNA. tRNA及rRNA同mRNA一样，都是染色体DNA的转录产物。 来自辞典例句
• You can't take the transfer students'exam without your transcripts. 没有成绩证明书，你就不能参加转学考试。 来自辞典例句

11 captioned   

a.标题项下的； 标题所说的

参考例句：

• This paper reviews the production, development and nationalization of the captioned materials. 本文就铜系合金引线框架材料的生产、发展和国产化进程作一论述。
• Please advise other considerable hotels for this captioned group. 请推荐其它一些高级的旅馆给这一群打标语的人。

12 doughty   

adj.勇猛的，坚强的

参考例句：

• Most of successful men have the characteristics of contumacy and doughty.绝大多数成功人士都有共同的特质：脾气倔强，性格刚强。
• The doughty old man battled his illness with fierce determination.坚强的老人用巨大毅力与疾病作斗争。