1、CloningUnit 2differvi.不同;相异ObjectiveTo learn some basic information about cloning.A clone is an animal or plant produced naturally or artificially from the cells of another animal or plant and is exactly the same as it.Cloning is a way of making an exactcopy of another animal or plant.The clone has
2、the same DNA as the parent.Whats cloning?Sounds Reasonable?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 typesof cloning technologies are:(1)recombinant DNA technology or DNA cloning（基因重组克
3、隆技术）(2)reproductive cloning（生殖性克隆）(3)therapeutic cloning（治疗性克隆）克隆一词是英文单词clone的音译，作为名词，clone通常被意译为无性繁殖系。同一克隆的所有成员的遗传构成是完全相同的，例外仅见于有突变发生时。自然界早已存在天然植物、动物和微生物的克隆。人们开始探索用人工的方法来生产高等动物克隆。这样，克隆一词就开始被用作动词，指人工培育克隆动物这一动作。目前，生产哺乳动物克隆的方法主要有胚胎分割和细胞核移植两种。克隆羊“多莉”，以及其后各国科学家培育的各种克隆动物，采用的都是细胞核移植技术。所谓细胞核移植，是指将不同发育时期的胚胎
4、或成体动物的细胞核，经显微手术和细胞融合方法移植到去核卵母细胞中，重新组成胚胎并使之发育成熟的过程。由于细胞核移植是产生克隆动物的有效方法，故人们往往把它称为动物克隆技术。In pairs,look at these pictures and discuss which ones are natural clones and which ones are man-made.Think about how they differ.QuizDolly the sheepA strawberry plantNatural cloneMan-made clone一株草莓依靠它沿地“爬走”的匍匐茎,一年
5、内就能长出数百株草莓苗。Growing new plantsTwinsNatural cloneMan-made cloneNatural clone is one that occurs in nature without human help.Man-made clone is one that is produced through human intervention(介入).CloneCan you tell the difference between natural clone and man-made clone?Cactus(仙人掌)Pendulum orchid(吊兰)na
6、tural clone examplesman-made clone examples Im celebrity in the history of cloning.Do you know my name?Dolly,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(严重的关节炎).Celeb
7、rity Sheep DollyDolly是世界上第一例用体细胞乳腺上皮细胞，通过细胞核移植技术，在复杂的人工操作下，得到的一只小绵羊。Scientists have been cloning animals for many years.The creation of Dolly isthe first mammal cloned from the cell of an adult animal.Since Dolly,researchers have cloned a number of large and small animals including sheep,goats,oxen,
8、mice,pigs,cats,rabbits and so on.All these clones were created using nuclear transfer technology(细胞核移植技术).What animals have been cloned?The mule in the picture is the worlds first cloned mule.It was born on 4 May 2003.His name is Idaho Gem.The kitten in the picture is called Cc.Its name is from“Copy
9、cat”.It was born in December 2002.These female pigs are also cloned.They are born on Christmas Day 2001.They are Noel,Angel,Star,Joy and Mary.The pair of calves were born on 5 July 1998 in Ishikawa,Japan.They were two years younger than Dolly,being second adult animal clones in the world.If possible
10、,do you want another person to be exactly the same as you?Why or why not?DiscussionImportant events in cloning historyIn 5000 B.C.(谷物选种)Human beings began to choose the best seeds from some kinds of crops.That was the beginning of controlling life according to humans will.In 1952:Cloning tadpole(克隆蝌
11、蚪)The American scientists created a copy of tadpole by means of using a tadpole cell.This tiny tadpole has become the first kind of cloning animal.In 1978:The first case of tube infant (试管婴儿)appeared.A British doctor used the sperm(精子)of a man and fertilized(使受精)it in a test tube(试管)and then transpl
12、anted (移植)the embryo(胚胎)into the womb (子宫)of a healthy mother.The first tube infant called Louis appeared.In 1996:The famous sheep“Dolly”was cloned successfully.Dolly is together with her mother.In 1998:A series of things were cloned.The scientists in Hawaii University cloned over 50 mice.Some priva
13、te institutions (协会)successfully cloned little oxen.Nowadays:Cloned dogs,mice,rabbits,goats,oxen,pigs appeared.China became the seventh country thathas the ability to clone pigs.China has succeededin using embryonic(胚胎的)cells to clone many animals.1 Clone can be from both natural clone and man-made
14、clone.2 The sheep,named Kitty was the first successful clone of a mammal.3 Only strawberries and cactuses(仙人掌)are natural clones.4 Since Dolly,researchers have cloned a number of large and small animals including cats,rabbits and horses.5 A parent can clone a child who is dying of a terminal illness
15、(不治之症).T or FAccording to what weve learned,in pairs discuss what you understand about cloning.Then list the questions you want to find out.Share your lists with one another.Questions about cloning1.How is a clone produced?2.What benefits can humans gain from cloning?3.What problems may arise when h
16、umans are cloned?1.How is a clone produced?The cloning of plants is simple and relatively easy.It can be done by taking cuttings(man-made cloning)or letting the plant produce its own runners(natural cloning).The cloning of animals is more complicated.It was not achieved until 1996.2.What benefits ca
17、n humans gain from cloning?1)Medical cloning can help cure serious illnesses that ruin ones quality of life(such as Parkinsons disease 帕金森氏症 or Alzheimers disease 阿尔茨海默氏症).2)It can help infertile people have babies.3.What problems may arise when humans are cloned?1)People may want to clone themselve
18、s so they can live forever.2)People may want to clone dead children.3)People may want to clone their favourite pets.ABA:I think cloning is good for us.Because B:I think cloning is bad for us.Because Is cloning good or bad for us?DebateThese expressions may help.Do you think it is wise to?Whats your opinion of?I think you should I agree with you that I would never accept Im happy to accept a clone but I would never accept a clone I dont mind but Homework1.Look up the new words and expressions of the Reading in the dictionary.2.Preview the Reading:CLONING:WHERE IS IT LEADING US?
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