新人教版英语选修8unit2 Warming up课件.ppt

Cloning,Unit2,Cloning?,Acloneisananimalorplantproducednaturallyorartificiallyfromthecellsofanotheranimalorplantandisexactlythesameasit.Cloningisawayofmakinganexactcopyofanotheranimalorplant.TheclonehasthesameDNAastheparent.,Whatscloning?,SoundsReasonable?,Therearedifferenttypesofcloning,andcloningtechnologiescanbeusedforotherpurposesbesidesproducingthegenetictwinofanotherorganism.Thethreetypesofcloningtechnologiesare:(1)recombinantDNAtechnologyorDNAcloning（基因重组克隆技术）(2)reproductivecloning（再生克隆技术）(3)therapeuticcloning（干细胞疗法克隆技术）,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,例如：同卵双胞胎实际上就是一种克隆。然而,天然的哺乳动物克隆的发生率极低,且缺乏目的性,所以很少能够被用来为人类造福。,因此,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。,Inpairs,lookatthesepicturesanddiscusswhichonesarenaturalclonesandwhichonesareman-made.Thinkabouthowtheydiffer.,Quiz,Dollythesheep,Astrawberryplant,Naturalclone,Man-madeclone,一株草莓依靠它沿地“爬走”的匍匐茎,一年内就能长出数百株草莓苗。,Growingnewplants,Twins,Naturalclone,Man-madeclone,Naturalcloneisonethatoccursinnaturewithouthumanhelp.,Man-madecloneisonethatisproducedthroughhumanintervention(介入).,Clone,Canyoutellthedifferencebetweennaturalcloneandman-madeclone?,Cactus(仙人掌),Pendulumorchid(吊兰),naturalcloneexamples,man-madecloneexamples,Imcelebrityinthehistoryofcloning.Doyouknowmyname?,Dolly,thefirstmammaltobeclonedfromadultDNA,wasputdownbylethalinjectiononFeb.14,2003.Priortoherdeath,Dollyhadbeensufferingfromlungcancerandcripplingarthritis(严重的关节炎).,CelebritySheepDolly,Dolly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。,Scientistshavebeencloninganimalsformanyyears.ThecreationofDollyisthefirstmammalclonedfromthecellofanadultanimal.SinceDolly,researchershaveclonedanumberoflargeandsmallanimalsincludingsheep,goats,oxen,mice,pigs,cats,rabbitsandsoon.Allthesecloneswerecreatedusingnucleartransfertechnology（细胞核移植技术）.,Whatanimalshavebeencloned?,Themuleinthepictureistheworldsfirstclonedmule.Itwasbornon4May2003.HisnameisIdahoGem.,ThekitteninthepictureiscalledCc.Itsnameisfrom“Copycat”.,ItwasborninDecember2002.,Thesefemalepigsarealsocloned.TheyarebornonChristmasDay2001.TheyareNoel,Angel,Star,JoyandMary.,Thepairofcalveswerebornon5July1998inIshikawa,Japan.TheyweretwoyearsyoungerthanDolly,beingsecondadultanimalclonesintheworld.,Ifpossible,doyouwantanotherpersontobeexactlythesameasyou?Whyorwhynot?,Discussion,Importanteventsincloninghistory,In5000B.C.(谷物选种)Humanbeingsbegantochoosethebestseedsfromsomekindsofcrops.Thatwasthebeginningofcontrollinglifeaccordingtohumanswill.,In1952:Cloningtadpole(克隆蝌蚪)TheAmericanscientistscreatedacopyoftadpolebymeansofusingatadpolecell.Thistinytadpolehasbecomethefirstkindofcloninganimal.,In1978:Thefirstcaseoftubeinfant(试管婴儿)appeared.ABritishdoctorusedthesperm(精液)ofamanandfertilized(受精)itinatesttube(试管)andthentransplanted(移植)theembryo(胚胎)intothewomb(子宫)ofahealthymother.ThefirsttubeinfantcalledLouisappeared.,DollyandtheFatherofDollyLanwilmut(伊恩.威尔姆),In1996:Thefamoussheep“Dolly”wasclonedsuccessfully.,Dollyistogetherwithhermother.,In1998:Aseriesofthingswerecloned.ThescientistsinHawaiiUniversityclonedover50mice.Someprivateinstitutions(协会)successfullyclonedlittleoxen.,Nowadays:Cloneddogs,mice,rabbits,goats,oxen,pigsappeared.Chinabecametheseventhcountrythathastheabilitytoclonepigs.Chinahassucceededinusingembryonic(胚胎的)cellstoclonemanyanimals.,1Clonecanbefrombothnaturalcloneandman-madeclone.2Thesheep,namedKittywasthefirstsuccessfulcloneofamammal.3Onlystrawberriesandcactuses(仙人掌)arenaturalclones.4SinceDolly,researchershaveclonedanumberoflargeandsmallanimalsincludingcats,rabbitsandhorses.Aparentcancloneachildwhoisdyingofaterminalillness(不治之症).,TorF,Accordingtowhatwevelearned,inpairsdiscusswhatyouunderstandaboutcloning.Thenlistthequestionsyouwanttofindout.Shareyourlistswithoneanother.,Questionsaboutcloning,1.Howisacloneproduced?2.Whatbenefitscanhumansgainfromcloning?3.Whatproblemsmayarisewhenhumansarecloned?,1.Howisacloneproduced?,Thecloningofplantsissimpleandrelativelyeasy.Itcanbedonebytakingcuttings(man-madecloning)orlettingtheplantproduceitsownrunners(naturalcloning).Thecloningofanimalsismorecomplicated.Itwasnotachieveduntil1996.,2.Whatbenefitscanhumansgainfromcloning?,1)Medicalcloningcanhelpcureseriousillnessesthatruinonesqualityoflife(suchasParkinsonsdisease帕金森氏症orAlzheimersdisease阿尔茨海默氏症).2)Itcanhelpinfertilepeoplehavebabies.,3.Whatproblemsmayarisewhenhumansarecloned?,1)Peoplemaywanttoclonethemselvessotheycanliveforever.2)Peoplemaywanttoclonedeadchildren.3)Peoplemaywanttoclonetheirfavoritepets.,A,B,A:Ithinkcloningisgoodforus.Because,B:Ithinkcloningisbadforus.Because,Iscloninggoodorbadforus?,Debate,Theseexpressionsmayhelp.,Doyouthinkitiswiseto?W