电脑桌面
添加小米粒文库到电脑桌面
安装后可以在桌面快捷访问

2014-2015学年高中英语 Unit 2 Cloning What is cloning素材 新人教版选修8

2014-2015学年高中英语 Unit 2 Cloning What is cloning素材 新人教版选修8_第1页
1/3
2014-2015学年高中英语 Unit 2 Cloning What is cloning素材 新人教版选修8_第2页
2/3
2014-2015学年高中英语 Unit 2 Cloning What is cloning素材 新人教版选修8_第3页
3/3
What is cloning?Cloning means the production of genetically identical animals. In 1995 scientists at the Roslin Institute in Edinburgh, Scotland produced Megan and Morag - two lambs cloned from a single embryo. In 1996 Dolly the sheep was produced, the first example of a clone produced not from an embryo cell but from a cell taken from an adult sheep. She was cloned using a nuclear transfer technique, where the nucleus from a cell taken from the mammary gland of an adult sheep was fused with an un fertilized egg from which the nucleus had been removed. 277 cells were fused in this way, resulting in 29 viable embryos which were implanted into surrogate Blackface ewes. One gave birth to Dolly. Dolly died in 2003 after suffering the signs of p remature ageing such as arthritis and a liver complaint.The 'production' of Dolly has sparked a cloning frenzy. 1998 saw the arrival of cows cloned using the same technique that produced M egan and Morag 1. The Roslin institute cloned the first pig in 2000 2. In the US in 2001 a rhesus macaque monkey called Tetra was cl oned 3. Also in the US in 2002 a cloned kitten was reported 4 in the same year as the first cloned rabbits in France 5. In 2003 the first cloned mule 6, horse 7 and rat 8 were reported.Animal welfareCloning involves many possibilities for detrimental effects on animals. For example, cloned lambs and calves are frequently abnormally large at birth - some have been twice normal size. One cloning expert admitted in 1992 that "many cloned calves are abnormal".9 In Australia, a l amb of five times the mean birth weight for the breed has been recorded. In addition, cloned animals are often found to have malformed internal or...

1、当您付费下载文档后,您只拥有了使用权限,并不意味着购买了版权,文档只能用于自身使用,不得用于其他商业用途(如 [转卖]进行直接盈利或[编辑后售卖]进行间接盈利)。
2、本站所有内容均由合作方或网友上传,本站不对文档的完整性、权威性及其观点立场正确性做任何保证或承诺!文档内容仅供研究参考,付费前请自行鉴别。
3、如文档内容存在违规,或者侵犯商业秘密、侵犯著作权等,请点击“违规举报”。

碎片内容

2014-2015学年高中英语 Unit 2 Cloning What is cloning素材 新人教版选修8

您可能关注的文档

确认删除?
VIP
微信客服
  • 扫码咨询
会员Q群
  • 会员专属群点击这里加入QQ群
客服邮箱
回到顶部