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托福听力练习-科学美国人60秒:多位点突变

2017-04-28 10:59:00来源：科学美国人60秒

点击查看>>科学美国人60秒音频：多位点突变

　　科学美国人60秒听力练习：多位点突变

　　科学美国人60秒英文文本

　　In a point mutation, a single letter of the genetic code changes to another letter. When a protein gets made from that new code, it’ll be slightly different from usual. But new research finds that it may be fairly common for multiple mutations to happen in DNA simultaneously. Which could make big evolutionary jumps possible immediately, without waiting for the changes to accrue over generations. The work is in the journal Current Biology. [Daniel Schrider, Jonathan Hourmozdi and Matthew Hahn, Pervasive Multinucleotide Mutational Events in Eukaryotes]

　　The researchers did close examinations of the genomes of organisms ranging from yeast to fruit flies to the plant Arabidopsis to humans. And they concluded that about three percent of all new mutations must be multiples. A likely explanation is that some polymerase enzyme is particularly prone to errors when it’s weaving a strand of DNA.

　　Here’s why having multiples could be a big deal. The single mutation-at-a-time view would be like hoping you hit the Pick 4 lottery by getting one number a day for four days. Sadly, what you really get is four losing tickets. But multiple mutations could let you hit the Pick 4 all at once. And win the evolutionary lottery.

　　—Steve Mirsky

　　中文翻译请点击下一页

本文关键字: 托福听力 科学美国人60秒

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