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SSS 2011-03-21

时间:2011-04-27 05:36来源:互联网 提供网友:geologyforget   字体: [ ]
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    (单词翻译:双击或拖选)

This is Scientific American's 60-Second Science. I'm Cynthia Graber. This will just take a minute.

Mark Twain called it "the most delicious fruit known to men." He was talking about the cherimoya. If you never heard of it, there's good reason. It has a feature that has prevented it from becoming widely popular—numerous big seeds fill its sweet white flesh.

But now scientists in Spain and at the University of California, Davis have found the key to making the cherimoya and related fruits seedless. They published their research in the Proceedings1 of the National Academy of Sciences.

It's generally tough to develop a seedless fruit—bananas and oranges are rare successes. Breeding for seedlessness usually fails to produce the fully3 developed fruit consumers demand. But the scientists found a spontaneous mutation4 that causes seedlessness in a cherimoya relative, the sugar apple. They compared its genome to that of a seedless mutant of a plant called Arabidopsis that's used in a lot of research.

In both cases, they found a deletion of one particular gene2. The researchers say this is the first time a gene for seedlessness has been determined5. If they can find a way to knock out that gene in the cherimoya, it could bring Mark Twain's favorite fruit, and many others, to a grocery store near you.

Thanks for the minute. For Scientific American's 60-Second Science, I'm Cynthia Graber.


点击收听单词发音收听单词发音  

1 proceedings Wk2zvX     
n.进程,过程,议程;诉讼(程序);公报
参考例句:
  • He was released on bail pending committal proceedings. 他交保获释正在候审。
  • to initiate legal proceedings against sb 对某人提起诉讼
2 gene WgKxx     
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。
3 fully Gfuzd     
adv.完全地,全部地,彻底地;充分地
参考例句:
  • The doctor asked me to breathe in,then to breathe out fully.医生让我先吸气,然后全部呼出。
  • They soon became fully integrated into the local community.他们很快就完全融入了当地人的圈子。
4 mutation t1PyM     
n.变化,变异,转变
参考例句:
  • People who have this mutation need less sleep than others.有这种突变的人需要的睡眠比其他人少。
  • So far the discussion has centered entirely around mutation in the strict sense.到目前为止,严格来讲,讨论完全集中于围绕突变问题上。
5 determined duszmP     
adj.坚定的;有决心的
参考例句:
  • I have determined on going to Tibet after graduation.我已决定毕业后去西藏。
  • He determined to view the rooms behind the office.他决定查看一下办公室后面的房间。
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