克隆介绍及优缺点.ppt

* Cloning is the creation of cells or whole animals using DNA(脱氧核糖核酸) from a single parent, bypassing(绕道而行) the normal reproductive process. The clone has the same DNA to the parent. There are different types of cloning, and cloning technologies can be used for other purposes besides producing the genetic twin of another organism. The three types of cloning technologies are: (1) recombinant DNA technology or DNA cloning（基因重组克隆技术） (2) reproductive cloning（再生克隆技术） (3) therapeutic cloning（干细胞疗法克隆技术）. -------the animal which had been first cloned Dolly(1996-2003) was a mother to six lambs, bred the old-fashioned way. Although most Finn Dorset sheep live to be 11 to 12 years of age, postmortem examination of Dolly seemed to indicate that, other than her cancer and arthritis, she appeared to be quite normal. The unnamed sheep from which Dolly was cloned had died several years prior to her creation. Dolly(1996-2003), the first mammal to be cloned from adult DNA, was put down by lethal injection on Feb. 14, 2003. Prior to her death, Dolly had been suffering from lung cancer and crippling arthritis. Scientists have been cloning animals for many years. In 1952, the first animal, a tadpole, was cloned. Before the creation of Dolly, the first mammal cloned from the cell of an adult animal, clones were created from embryonic cells. Since Dolly, researchers have cloned a number of large and small animals including sheep, goats, cows, mice, pigs, cats, rabbits, and a gaur. All these clones were created using nuclear transfer technology（细胞核移植技术）. Dolly Cloned monkeys First cloned mule Cloned twin goats First cloned horse First cloned cats Cloning(克隆技术) is the most attractive story of the new biotechnologies(生物技术) and the one which causes the most heated discussion over its worth. Here are answers to the most common questions about cloning Question1: Is cloning unnatural? Answer: No. Clones are always produced by natu