【正文】 Unit 8 Teaching Objectives 1. Enlarge vocabulary 2. Talk about the advantages and disadvantages cloning brings to us 3. Learn to identify the writer’s purpose 4. Learn to write a letter of thanks Sections Section A Legal and Moral Implications of Cloning Section B Who Will Take Advantage of Human Cloning? Section C Twins Six Years Apart Section A Legal and Moral Implications of Cloning Table of Contents ? Background Information ? Warmingup Activities ? Text Analysis ? Vocabulary and Structure ? Vocabulary Test ? Writing There are different types of cloning, and cloning technologies can be used for other purposes besides producing the geic twin of another anism. The three types of cloning technologies are: (1) rebinant DNA technology or DNA cloning（ 基因重組克隆技術(shù)） , (2) reproductive cloning（ 再生克隆技術(shù)） , and (3) therapeutic cloning（ 干細(xì)胞療法克隆技術(shù)） . What is cloning ? Dolly, the first mammal to be cloned from adult DNA, was put down by lethal injection on Feb. 14, 2023. Prior to her death, Dolly had been suffering from lung cancer and crippling arthritis. Celebrity Sheep Dolly (1) 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 Celebrity Sheep Dolly (2) prior to her creation. Dolly was a mother to six lambs, bred the oldfashioned way. 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（ 細(xì)胞核移植技術(shù)） . What animals have been cloned? (1) Dolly Cloned monkeys First cloned mule What animals have been cloned? (2) Cloned twin goats First cloned horse First cloned cat Reproductive cloning is expensive and highly inefficient. More than 90% of cloning attempts fail to produce viable offspring. More than 100 nuclear transfer procedures could be required to produce one viable clone. In addition to low success rates, cloned animals tend to have more promised immune function and higher rates of infection, tumor growth, and other disorders. What are the risks of cloning? (1) Japanese studies have shown that cloned mice live in poor health and die early. About a third of the cloned calves born alive have died young, and many of them were abnormally large. Many cloned animals have not lived long enough to generate good data about how clones age. Appearing healthy at a young age unfortunately is not a good indicator of long term survival. Clones have been known to die mysteriously. What are the risks of cloning?(2) Group Discussions (1) 1. As far as you know, what are the advantages and disadvantages that cloning brings to us? Some fatal diseases can be cured with the application of cloning。 the rate of success in an transplant will be greatly improved。 and the infertile couples are hopeful to have their own babies, etc. However, it may bring confusion and fear to us。 it will threaten human society and dignity。 and those clones may feel miserable if they are treated as an donors instead of independent human beings. Group Discussions (2) 2. Should Humans be cloned? Due to the inefficiency of animal cloning and the lack of understanding about this technology, I’m strongly against it. Not only do most attempts to clone mammals fail, several cloned animals have died prematurely from infections. Moreover, we don’t know how cloning could impact mental development, which is crucial for the development of healthy humans. With so many unknowns concerning reproductive cloning, the attempt to clone humans at this time is considered potentially dangerous and ethically irresponsible. Comprehension of the Text (1) 1. How did the world react to the first successfully cloned sheep? The world was amazed by the news at first, then worried about and puzzled over a long list of wild possibilities. Comprehension of the Text (2) 2. What are the two broad categories human cloning situations often fall into? One of the situations is that parents want to clone a child who can serve either as a transplant donor or as a substitute for the original. The second is that adults want to clone themselves for a variety of reasons. Comprehension of the Text (3) 3. According to the author, why are twins more alike than clones? Because clones are only physically identical while twins share the same environment within the mother and are usually raised in the same family. Comprehension of the Text (4) 4. Biologically speaking, what is the only possible major difference between a clone and the original? The only possible major difference is bearing children, as scientists are not sure if Dolly will be able to have lambs. Comprehension of the Text (5) 5. Why do some parents want to save their fatally ill child through cloning? 6. Could cloned animals be used as an donors? Because cloning would increase the chances for a tissue match from 25 percent to nearly 100 percent. If technology was improved, this could be realized. Comprehension of the Text (6) 7. How did Judith Martin suggest referring to one’s DNA donors?