英语沙龙十年合集珍藏版第三辑Cloning1) Humans May Have It Easier

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Cloning¹⁾ Humans May Have It Easier

Most scientists agreed that cloning an entire human being －－besides being morally question－able －－was fraught with technical obstacles²⁾．After all，research into animal cloning has already shown that there are hundreds of failures，including many badly deformed³⁾ creatures that were usually miscarried⁴⁾．

Now comes word that it might be easier to clone humans than was previously believed．People have a genetic quirk that might pr event some of the developmental deformities associated with animal cloning．One gene，called IGF２R，is normally imprinted⁵⁾ in sheep，cows and mice but not in humans．Human clones would always inherit nonimprinted IGF２R genes，so t here would be no chance of a mix－up and，their growth would be normal．But what of the other４９or so imprinted genes？No one knows what trouble they might cause．So the fact that humans have one less imprinted gene than mice，sheep or cows means that human cloning might be marginally easier，but not necessarily safer．

克隆人类也许更容易

许多科学家都认为克隆一个完整的人---除了在伦理上令人怀疑外---还存有许多技术障碍。毕竟，对动物克隆的深入研究已经表明有上百个失败案例，包括许多因严重畸形而通常流产的动物。

现在有消息说克隆人可能比以前所认为的要容易。人类有一种基因突变可以防止一些与动物克隆相关的发育畸形。一种叫做IGF２R的基因，通常遗传到绵羊、奶牛和老鼠，但不在人类身上。人类克隆一直是继承非遗传性的IGF２R基因，所以不会造成混乱，他们的发育将是正常的。但是另外约４９个遗传基因会怎样呢？没有人能够知道他们会造成什么样的麻烦。所以人类比老鼠、绵羊和奶牛少一个遗传基因这一事实意味着克隆人类可能稍容易一些，但并不一定更安全。