What is cloning? Are there different types of cloning?71 Actually, there are different tec

What is cloning? Are there different types of cloning?
71 Actually, there are different technologies which can be used for other purpose besides producing the genetic twin of another organism. A basic understanding of the different types of cloning is key to talking an informed stance on current public policy issues and making the best possible personal decisions. The following three types of cloning technologies are usually performed; recombinant DNA technology or DNA cloning, reproductive cloning, and therapeutic cloning.
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Scientists have been cloning animals for many years. In 1952, the first animal, a tadpole, was cloned. 73 Since Dolly, researchers have cloned a number of large and small animals including sheep, goats, cows, mice, pigs, cats, rabbits, and a gaur. 74
Hundreds of cloned animals exist today, but the number of different species is limited. 75 Some species may be more resistant to somatic cell nuclear transfer than others. The process of stripping the nucleus from an egg cell and replacing it with the nucleus of a donor cell is a traumatic one, and improvements in cloning technologies may be needed before many species can be cloned successfully.A．What animals have been cloned?B．All these clones were created using nuclear transfer technologyC．When the media report on cloning in the news, they are usually talking about only one type called reproductive cloning.D．Recently Chinese scientists have also successfully cloned mammals such as an ox.E. Cloning is making a genetic copy of something else.
F. Attempts at cloning certain species such as monkeys, chickens, horses, and dogs, have been unsuccessful.
G. Before the creation of Dolly, the first mammal cloned from the cell of an adult animal, clones were created from embryonic cells.C

(答案→)C 解析：【小题1】C 根据下句：实际上有不同的克隆技术。说明前面这句话谈的是报道的往往只有一种克隆技术。故C符合要求。【小题2】A 根据下一段提及了很多动物都被成功的克隆，可知这里询问的是何种动物被克隆？【小题3】G 根据下一句：自从多利被克隆出以后…；可知这句应该谈论的多利被克隆之前的事情。【小题4】Ｂ　根据下一段可知上面提及的那些克隆出的动物都是运用nuclear transfer这种技术的。【小题5】F 根据下一句这些动物有抗体可知很多动物用nuclear transfer这种技术无法克隆成功。

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