VOA慢速英语2009年-Agriculture Report - Learning the Secrets

This is the VOA Special English Agriculture Report.

Scientists now have a genetic¹ map of the potato. The project is the work of a team from fourteen countries, the Potato Genome Sequencing Consortium.

Potatoes are one of the world's leading food crops. But potato breeders currently spend ten to twelve years developing new kinds. Now they will be able to locate genes² for any desired trait, improving quality, nutritional³ value and disease resistance.
　
A farmer in northern Germany plants a genetically⁴ engineered kind of potato in a test field

A genome contains information about every position along chromosomes⁵, the structures that hold genes. Genes direct the making of proteins which do much of the work in building an organism, whether a person or a potato. A potato has twelve chromosomes and about eight hundred forty million base pairs. This is about one-fourth the size of the human genome.

The potato genome is not yet final but it shows the order of ninety-five percent of the genes. Most potato varieties carry four separate copies of their genes. But the researchers did much of their work with a phureja, a kind of a potato that has only one copy. Richard Veilleux, a professor at Virginia Tech, provided that variety of potato.

Plant biologist Robin⁶ Buell at Michigan State University also worked on the genome. She says it will improve understanding of other crops because potatoes are related to tomatoes, peppers and eggplants.

In a separate development, another team reported completing a genome of the organism responsible for late blight⁷. That disease can infect potatoes, tomatoes and some other plants. It causes several billion dollars a year in agricultural losses around the world.

But late blight was also the cause of the potato famine in Ireland in the middle of the eighteen hundreds. Potato shortages caused at least one million deaths and a wave of Irish immigration to America.

The scientists say that in the short term, studies based on the new genome may help explain why the pathogen has been so aggressive. And in the long term, they say, knowing where different genetic traits may be found on the map could lead to better plants. It could also reduce the need for chemicals.

Completion of the project was announced in the journal Nature. Researchers at Harvard University and the Massachusetts Institute of Technology led the work.

And that's the VOA Special English Agriculture Report, written by Jerilyn Watson. You can find all of our reports, with transcripts⁸ and MP3s, at voaspecialenglish.com. I'm Bob Doughty⁹.

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 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 nutritional   

adj.营养的，滋养的

参考例句：

• A diet lacking in nutritional value will not keep a person healthy.缺乏营养价值的饮食不能维持人的健康。
• The labels on food products give a lot of information about their nutritional content.食品上的标签提供很多关于营养成分的信息。

4 genetically   

adv.遗传上

参考例句：

• All the bees in the colony are genetically related. 同一群体的蜜蜂都有亲缘关系。
• Genetically modified foods have already arrived on American dinner tables. 经基因改造加工过的食物已端上了美国人的餐桌。 来自英汉非文学 - 生命科学 - 基因与食物

5 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》

6 robin   

n.知更鸟，红襟鸟

参考例句：

• The robin is the messenger of spring.知更鸟是报春的使者。
• We knew spring was coming as we had seen a robin.我们看见了一只知更鸟，知道春天要到了。

7 blight   

n.枯萎病；造成破坏的因素；vt.破坏，摧残

参考例句：

• The apple crop was wiped out by blight.枯萎病使苹果全无收成。
• There is a blight on all his efforts.他的一切努力都遭到挫折。

8 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

9 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。