《基础医学英语2.ppt

Unit 11 Cloning and Genes Word Formation re- 再,重 Group Discussion 1. What is cloning ? 2. Do you know anything about the sheep “Dolly”? 3. What is the significance of clone technique ? The term clone is derived from κλ?ν, the Greek word for twig, branch, referring to the process whereby a new plant can be created from a twig. In horticulture(园艺学), the spelling clon was used until the twentieth century; the final e came into use to indicate the vowel is a long o instead of a short “o ”. Since the term entered the popular lexicon in a more general context, the spelling clone has been used exclusively. Cloning is the process of creating an identical copy of something. In biology, it collectively refers to processes used to create copies of DNA fragments (molecular cloning), cells (cell cloning), or organisms. The term also encompasses situations whereby organisms reproduce asexually. The topic of the human cloning has provoked numerous discussions of ethics, morality, religion.... There are three types of cloning: embryo cloning, adult DNA cloning and therapeutic cloning. Dolly and her first-born lamb, Bonnie Dolly (1996-07-05 – 2003-02-14), a Finn Dorsett ewe(母 羊), was the first mammal to have been successfully cloned from an adult cell. She was cloned at the Roslin Institute in Scotland and lived there until her death when she was six. On 2003-04-09 her stuffed remains were placed at Edinburghs Royal Museum, part of the National Museums of Scotland. Dolly was publically significant because the effort showed that the genetic material from a specific adult cell, programmed to express only a distinct subset of its genes, could be reprogrammed to grow an entire new organism. Before this demonstration, there was no proof for the widely spread hypothesis that differentiated animal cells can give rise to entire