动植物细胞工程

1、会计学1动植物细胞工程动植物细胞工程Figure4-2The fibroblast.(A)Phase-contrastmicrographoffibroblastsinculture.(B)Drawingsofalivingfibroblastlikecellinthetransparenttailofatadpole,showingthechangesinitsshapeandpositiononsuccessivedays.Notethatwhilefibroblastsflattenoutinculture,theycanhavemorecomplex,process-bearingmo

2、rphologiesintissues.(A,courtesyofDanielZicha;B,redrawnfromE.Clark,Am. J. Anat.13:351-379,1912.)Cells/tissues grown in culture long period of timeBASIC STERILE TECHNIQUEWork environment and surfacePlasticware and glasswareHandling techniquesSterilization of solutions for maintenancegrowth or treatmen

3、tnWORK ENVIRONMENT AND SURFACEnLaminar flow hoodn Relatively enclosed spacen Little traffic flowing past work spacen Confined space can be easily cleaned and maintainedn Must have annual checkup of HEPA filtersn Should have internal outlets for electricity, vacuum and gasn Frequently outfitted with

4、UV lightn Prevent contamination by daily scrub with 70% ethanoln Use closed flask attached to vacuum for spent mediumnSeparate sterile roomn All incoming air circulated through HEPA filtersnPLASTICWARE AND GLASSWAREnPipettes, bottles, flasks, petri dishesnPlasticn- better attachment and cell growth

5、of monolayer cell culturen- more expensive than reusable glassn- suitable for storage at 4CnGlassn- Can withstand temperatures 0C use for maintaining frozen stocksn- Steam sterilize by autoclavingn* relies on steam pressure and high heatn* use fast-dry cycle to dry condensaten* use “wet” cycle for s

6、alt solutions toprevent evaporationn* loosely place caps on bottles生长因子多为肽激素，有胰岛素、表皮生长因素（EGF）、成纤细胞生长因素（fibroblastgfowthfactor，FGF）、血小板来源增殖因素（plateletderivedgrowthfactor，PDGF）以及生长激素释放抑制因子（somatostatinSRIH）DMEM培养基培养基胎牛血清胎牛血清其他成分其他成分锥形瓶逐级锥形瓶逐级放大培养放大培养加碱（碳酸加碱（碳酸氢钠）氢钠）加糖（葡萄加糖（葡萄糖）糖）灌注培养液灌注培养液微载体微载体5L种子罐培

7、种子罐培养养培养液培养液50L生生物物反反应应器器接种狂犬接种狂犬病毒病毒出液口出液口收获病毒收获病毒组织工程（TissueEngineering）是近年来正在兴起的一门新兴学科，组织工程一词最早是由美国国家科学基金会1987年正式提出和确定的。它是应用生命科学和工程学的原理与技术，在正确认识哺乳动物的正常及病理两种状态下结构与功能关系的基础上，研究、开发用于修复、维护、促进人体各种组织或器官损伤后的功能和形态生物替代物的科学。组织工程的核心就是建立细胞与生物材料的三维空间复合体，即具有生命力的活体组织，用以对病损组织进行形态、结构和功能的重建并达到永久性替代。共基本原理和方法是将体外培养扩增

8、的正常组织细胞，吸附于一种生物相容性良好并可被机体吸收的生物材料上形成复合物，将细胞-生物材料复合物植入机体组织、器官的病损病分，细胞在生物材料逐渐被机体降解吸收的过程中形成新的在形态和功能方面与相应器官、组织相一致的组织，而达到修复创伤和重建功能的目的。生物相容性好、可被人体降解吸收的组织工程支架材料称为细胞外基质（ECM），其功能是为细胞提供生存空间，使细胞获足够的营养物质，进行气体交换，并使细胞按预制形态的三维支架生长。在细胞和生物材料的复合体植入机体病损部位后，生物支架被降解吸收，但种植的细胞继续增殖繁殖，形成新的具有原来特殊功能和形态的相应组织器官。种子细胞:自体、同种异体、异种组织

9、细胞等细胞外基质（extracelluarmatrix,ECM）:理想的ECM应具有以下特点：生物相容性好，在体内不引起炎症反应和毒性反应；有可吸收性，能彻底地被自身组织所取代；有可塑性，可塑为任意的三维结构，植入后在体内仍可保持特定形状；表面化学特性和表面微结构利于细胞的粘附和生长；降解速率可根据不同细胞的组织再生速率而进行调整。天然:胶原人工:聚乳酸（polylacticacidPLA）、聚羟基乙酸（polyglycolicacidPGA）、两者的共聚物（PGA-PLA）、聚-羟基丁酯（PHB）；聚乳酸-已内酯的共聚物（PLC）、聚原酸酯、聚磷本酯、聚酸酐等。组织工程临床应用:组织工程中临

10、床应用是在组织构建完成了动物试验之后，在人体上的应用，这也是组织工程的最后一步。目前，组织工程的研究只有活性皮肤达到了这一步。Figure22-1Mammalian skin.(A)Schematicdiagramsshowingthecellulararchitectureofthickskin.(B)Photographofacross-sectionthroughthesoleofahumanfoot,stainedwithhematoxylinandeosin.Theskincanbeviewedasalargeorgancomposedoftwomaintissues:epithel

11、ialtissue(theepidermis),whichliesoutermost,andconnectivetissue,whichconsistsofthetoughdermis(fromwhichleatherismade)andtheunderlyingfattyhypodermis.Eachtissueiscomposedofavarietyofcelltypes.Thedermisandhypodermisarerichlysuppliedwithbloodvesselsandnerves.Somenervefibersextendalsointotheepidermis.Fig

12、ure22-19Cross-section of mammalian epidermis.(A)Schematicdiagram.(B)Photomicrographofasectionthroughthesoleofthefoot(hematoxylinandVanGiesonstain).Thegranular cellsbetweenthepricklecellsandtheflattenedsquamesareinthepenultimatestagesofkeratinization;theyappeargranularbecausetheycontaindarklystaining

13、aggregatesofamaterialcalledkeratohyalin,whichisthoughttobeinvolvedintheintracellularcompactionandcross-linkingofthekeratin.Keratohyalinconsistsmainlyofaproteinknownasfilaggrin.Inadditiontothecellsdestinedforkeratinization,thedeeplayersoftheepidermisincludesmallnumbersofcellsofdifferentcharacter(nots

14、hownhere)includingmacrophagelikeLangerhanscells,derivedfrombonemarrow;melanocytes,derivedfromtheneuralcrest;andMerkel cells,whichareassociatedwithnerveendingsintheepidermis.SeealsoFigure22-1.Figure22-21The columnar organization of squames in the epidermal layer of thin skin.Thestructureisrevealedbys

15、wellingthekeratinizedsquamesinasolutioncontainingsodiumhydroxide.Thistypeoforganizationoccursonlywheretheepidermisisthin.Somestudiessuggestthateachsuchcolumnisaproliferativeunit,correspondingtoasinglestemcellamongthe10-12basalcellsonwhichthecolumnrests.Figure22-22An immortal stem cell.Eachself-renew

16、ingpatchofepidermismustcontainineachcellgenerationatleastoneimmortalstemcell,whosedescendantswillstillbepresentinthepatchinthedistantfuture.Thearrowsindicatelinesofdescent.Animmortalstemcellisshownhereoccupyingthesamepositionineachcellgeneration.Otherbasalcellsmightbebornchemicallydifferentinawaytha

17、tcommitsthemtoleavethebasallayeranddifferentiate;ortheytoomightbestemcells,equivalenttotheimmortalstemcellincharacterandmortalonlyinthesensethattheirprogenyhappensubsequentlytobejostledoutofthebasallayerandshedfromtheskin.Figure22-37Myoblast fusion in culture.Thephase-contrastmicrographsshowhowthece

18、llswillproliferate,lineup,andfusetoformmultinucleatemusclecells.(C)isathighermagnification,showingthecross-striationsthatarejustbeginningtobevisibleasthecontractileapparatusdevelops(red arrow)andtheaccumulationsofmanynucleiwithinasinglecell(green arrows).(CourtesyofRosalindZalin.)Figure22-39Autoradi

19、ograph of a single multinucleate muscle cell with associated satellite cells.ThefiberhasbeenisolatedfromanadultratandtransferredintoculturemediumcontainingH-thymidineplusanextractfromdamagedmusclethatstimulatesthesatellitecellstodivide.Thedividingsatellitecells(arrows)havebecomeradioactivelylabeled(

20、silvergrainsvisibleasblack dots);themusclecellnucleiareunabletoproliferateandremainunlabeled.(FromR.Bischoff,Dev. Biol.115:140-147,1986.)Figure21-99A typical neuron of a vertebrate.Thearrowsindicatethedirectioninwhichsignalsareconveyed.Theneuronshownisfromtheretinaofamonkey.Thelongestandlargestneuro

21、nsinahumanextendforabout1millionmmandhaveanaxondiameterof15mm.Figure21-100The complex organization of nerve cell connections.Thissemischematicdrawingdepictsasectionthroughasmallpartofamammalianbraintheolfactorybulbofadog,stainedbytheGolgitechnique.Theblackobjectsareneurons;thethinlinesareaxonsandden

22、drites,throughwhichthevarioussetsofneuronsareinterconnectedaccordingtopreciserules.Figure21-101The three phases of neural development.Figure21-102Diagram of an early (2 1/2-day) chick embryo, showing the origins of the nervous system.Theneuraltube(light green)hasalreadyclosed,exceptatthetailend,andl

23、iesinternally,beneaththeectoderm,ofwhichitwasoriginallyapart.Theneuralcrest(red)liesdorsallybeneaththeectoderm,inorabovetheroofoftheneuraltube.Inaddition,thickenings,orplacodes(dark green),intheectodermoftheheadgiverisetosomeofthesensorytransducercellsandneuronsofthatregion,includingthoseoftheearand

24、thenose.Thecellsoftheretinaoftheeye,bycontrast,originateaspartoftheneuraltube.Figure21-103Formation of the neural tube.Thescanningelectronmicrographshowsacross-sectionthroughthetrunkofa2-daychickembryo.Theneuraltubeisabouttocloseandpinchofffromtheectoderm;atthisstageitconsists(inthechick)ofanepithel

25、iumthatisonlyonecellthick.Figure21-109NGF effects on neurite outgrowth.Dark-fieldphotomicrographsofasympatheticganglionculturedfor48hourswith(above)orwithout(below)NGF.NeuritesgrowoutfromthesympatheticneuronsonlyifNGFispresentinthemedium.EachculturealsocontainsSchwann(glial)cellsthathavemigratedouto

26、ftheganglion;thesearenotaffectedbyNGF.NeuronalsurvivalandmaintenanceofgrowthconesforneuriteextensionrepresenttwodistincteffectsofNGF.Theeffectongrowthconesislocal,direct,rapid,andindependentofcommunicationwiththecellbody;whenNGFisremoved,thedeprivedgrowthconeshalttheirmovementswithinaminuteortwo.The

27、effectofNGFoncellsurvivalislessimmediateandisassociatedwithuptakeofNGFbyendocytosisanditsintracellulartransportbacktothecellbody.Figure22-43The growth of cartilage.Thetissueexpandsasthechondrocytesdivideandmakemorematrix.Thefreshlysynthesizedmatrixwithwhicheachcellsurroundsitselfisshadeddark green.

28、Cartilagemayalsogrowbyrecruitingfibroblastsfromthesurroundingtissueandconvertingthemintochondrocytes.Figure22-44Deposition of bone matrix by osteoblasts.Osteoblastsliningthesurfaceofbonesecretetheorganicmatrixofbone(osteoid)andareconvertedintoosteocytesastheybecomeembeddedinthismatrix.Thematrixcalci

29、fiessoonafterithasbeendeposited.Theosteoblaststhemselvesarethoughttoderivefromosteogenicstemcellsthatarecloselyrelatedtofibroblasts.Figure22-45An osteoclast shown in cross-section.Thisgiant,multinucleatedcellerodesbonematrix.Theruffledborderisasiteofsecretionofacids(todissolvetheboneminerals)andhydr

30、olases(todigesttheorganiccomponentsofthematrix).Osteoclastsvaryinshape,aremotile,andoftensendoutprocessestoresorbboneatmultiplesites.Theydevelopfrommonocytesandcanbeviewedasspecializedmacrophages.(FromR.V.Krstic,UltrastructureoftheMammalianCell:AnAtlas.Berlin:Springer,1979.)Figure22-46The remodeling

31、 of compact bone.Osteoclastsactingtogetherinasmallgroupexcavateatunnelthroughtheoldbone,advancingatarateofabout50mmperday.Osteoblastsenterthetunnelbehindthem,lineitswalls,andbegintoformnewbone,depositinglayersofmatrixatarateof1or2mmperday.Atthesametimeacapillarysproutsdownthecenterofthetunnel.Thetun

32、nelwilleventuallybecomefilledwithconcentriclayersofnewbone,withonlyanarrowcentralcanalremaining.Eachsuchcanal,besidesprovidingarouteofaccessforosteoclastsandosteoblasts,containsoneormorebloodvesselsbringingthenutrientsthebonecellsmusthavetosurvive.Typically,about5-10%oftheboneinahealthyadultmammalis

33、replacedinthiswayeachyear.Figure22-47Transverse section through a compact outer portion of a long bone.Themicrographshowstheoutlinesoftunnelsformedbyosteoclastsandthenfilledinbyosteoblastsduringsuccessiveroundsofboneremodeling.Thesectionhasbeenpreparedbygrinding;thehardmatrixhasbeenpreservedbutnotth

34、ecells.Lacunaeandcanaliculithatwereoccupiedbyosteocytesareclearlyvisible,however.Thealternatingbrightanddarkconcentricringscorrespondtoanalternatingorientationofthecollagenfibersinthesuccessivelayersofbonematrixlaiddownbytheosteoblaststhatlinedthewallofthecanalduringlife.(Thispatternisrevealedhereby

35、viewingthespecimenbetweenpartlycrossedPolaroidfilters.)Notehowoldersystemsofconcentriclayersofbonehavebeenpartlycutthroughandreplacedbynewersystems.Figure22-48The development of a long bone.Longbones,suchasthefemurorthehumerus,developfromaminiaturecartilagemodel.Uncalcifiedcartilageisshowningreen,ca

36、lcifiedcartilageinblack,boneinbrown,andbloodvesselsinred.Thecartilageisnotconvertedtobonebutisgraduallyreplacedbyitthroughtheactionofosteoclastsandosteoblasts,whichinvadethecartilageinassociationwithbloodvessels.Osteoclastserodecartilageandbonematrix,whileosteoblastssecretebonematrix.Theprocessofoss

37、ificationbeginsintheembryoandisnotcompleteduntiltheendofpuberty.Theresultingboneconsistsofathick-walledhollowcylinderofcompactboneenclosingalargecentralcavityoccupiedbythebonemarrow.Notethatnotallbonesdevelopinthisway.Themembrane bonesoftheskull,forexample,areformeddirectlyasbonyplates,notfromaprior

38、cartilagemodel.Figure22-49Remodeling of a long bone in the leg after a fracture that has healed out of true.Thedeformityintherecentlyhealedboneexposesittoabnormalstresses.Wherethecompressiveforcesareincreased,therateofbonedepositionisincreasedrelativetotherateoferosion;wheretheforcesaredecreased,the

39、rateofdepositionisdecreasedrelativetotherateoferosion.Inthiswaytheboneisgraduallyremodeledbacktoitsnormalform.Figure22-13Angiogenesis.Anewbloodcapillaryformsbythesproutingofanendothelialcellfromthewallofanexistingsmallvessel.Thisschematicdiagramisbasedonobservationsofcellsinthetransparenttailofalivi

40、ngtadpole.(AfterC.C.Speidel,Am. J. Anat.52:1-79,1933.)Figure22-14Capillary formation in vitro.Endothelialcellsinculturespontaneouslydevelopinternalvacuolesthatjoinup,givingrisetoanetworkofcapillarytubes.Photographs(A)and(B)showsuccessivestagesintheprocess;thearrowin(A)indicatesavacuoleforminginitial

41、lyinasingleendothelialcell.Theculturesaresetupfromsmallpatchesoftwotofourendothelialcellstakenfromshortsegmentsofcapillary.Thesecellswillsettleonthesurfaceofacollagen-coatedculturedishandformasmallflattenedcolonythatenlargesgraduallyasthecellsproliferate.Thecolonyspreadsacrossthedish,andeventually,a

42、fterabout20days,capillarytubesbegintoforminthecentralregions.Oncetubeformationhasstarted,branchessoonappear,andafter5to10moredaysanextensivenetworkoftubesisvisible,asseenin(B).Figure22-25White blood cells.(A-D)Electronmicrographsshowing,respectively,aneutrophil,abasophil,aneosinophil,andamonocyte.El

43、ectronmicrographsoflymphocytesareshowninFigure23-4.Eachofthecelltypesshownherehasadifferentfunction,whichisreflectedinthedistinctivetypesofsecretorygranulesandlysosomesitcontains.Thereisonlyonenucleuspercell,butithasanirregularlobedshape,andin(B),(C),and(D)theconnectionsbetweenthelobesareoutofthepla

44、neofsection.(E)LightmicrographofabloodsmearstainedwiththeRomanowskystain,whichcolorsthewhitebloodcellsstrongly.(A-D,courtesyofDorothyBainton;E,courtesyofDavidMason.)Figure22-27Bone marrow.(A)Lightmicrographofastainedsection.Thelargeemptyspacescorrespondtofatcells,whosefattycontentshavebeendissolveda

45、wayduringspecimenpreparation.Thegiantcellwithalobednucleusisamegakaryocyte.(B)Low-magnificationelectronmicrograph.Thistissueisthemainsourceofnewbloodcells(exceptforTlymphocytes,whichareproducedinthethymus).Notethattheimmaturebloodcellsofaparticulartypetendtoclusterinfamilygroups.(A,courtesyofDavidMa

46、son;B,fromJ.A.G.Rhodin,Histology:ATextandAtlas.NewYork:OxfordUniversityPress,1974.)Figure22-30A tentative scheme of hemopoiesis.Thepluripotentstemcellnormallydividesinfrequentlytogenerateeithermorepluripotentstemcells(self-renewal)orcommitted progenitor cells(labeledCFC=colony-formingcells),whichare

47、irreversiblydeterminedtoproduceonlyoneorafewtypesofbloodcells.Theprogenitorcellsarestimulatedtoproliferatebyspecificgrowthfactorsbutprogressivelylosetheircapacityfordivisionanddevelopintoterminallydifferentiatedbloodcells,whichusuallyliveforonlyafewdaysorweeks.Inadultmammalsallofthecellsshowndevelop

48、mainlyinthebonemarrowexceptforTlymphocytes,whichdevelopinthethymus,andmacrophagesandosteoclasts,whichdevelopfrombloodmonocytes.ThemostcontroversialpartoftheschemeiswheretheprecursorsforTandBlymphocytesfitintothescheme.Thedashedlinesreflectthisuncertainty.Thepluripotentstemcellsalsogiverisetovarioust

49、ypesoftissuecellsnotshowninthisscheme,suchasNKcells,mastcells,andavarietyofclassesofantigen-presentingcells(discussedinChapter23),butthepathwaysbywhichthesecellsdevelopareuncertain.Figure22-32The development of red blood cells.ThedrawingshowstherelationshipbetweentheBFC-E,theCFC-E,andthematureerythr

50、ocyte.BFC-EsandCFC-Esarebothcommittederythroidprogenitorcells.BFC-EsrespondtothefactorIL-3butnottoerythropoietin,whereasCFC-Esrespondtoerythropoietin.Theseriesofcelldivisionsthatoccurinthislineageundertheinfluenceoferythropoietinprovidesapowerfulmeansofcontrollingtheproductionoferythrocyteswithoutup

51、settingtheproductionofothertypesofbloodcells.Figure22-16Renewal of the gut lining.(A)Thepatternofcellturnoverandtheproliferationofstemcellsintheepitheliumthatformstheliningofthesmallintestine.Thenondividingdifferentiatedcellsatthebaseofthecryptsalsohaveafinitelifetime,terminatedbyprogrammedcelldeath

52、,andarecontinuallyreplacedbyprogenyofthestemcells.(B)Photographofasectionofpartoftheliningofthesmallintestine,showingthevilliandcrypts.Notehowmucus-secretinggobletcells(stainedred)areinterspersedamongtheabsorptivebrush-bordercellsintheepitheliumofthevilli.SeeFigure22-9forthestructureofthesecells.Mil

53、estones in Stem Cell ResearchMouse ES cells (Evens MJ and Kaufman, 1981)Cloning of Dolly (Wilmut, 1997)Establishing human ES cells (Thomson, 1998Trans-differentiation (Goodale; Verfaillie, 2003)Human ES cells by SCNT (Huang, 2005)Generation of iPS cells (Yamanaka, 2006）The definition of a stem cell.

54、Eachdaughterproducedwhenastemcelldividescaneitherremainastemcellorgoontobecometerminallydifferentiated.Figure21-29The early stages of mouse development.Figure21-30Scanning electron micrographs of the early mouse embryo.Thezonapellucidahasbeenremoved.(A)Two-cellstage.(B)Four-cellstage(apolarbodyisvis

55、ibleinadditiontothefourblastomeresseeFigure20-16).(C)Eight-to-sixteen-cellmorulacompactionoccurring.(D)Blastocyst.Figure21-31A procedure for creating a chimeric mouse.Twomorulaeofdifferentgenotypesarecombined.Figure21-32Making a chimeric mouse with ES or teratocarcinoma stem cells.Theexperimentshows

56、thatthestemcellscancombinewiththecellsofanormalblastocysttoformahealthychimericmouse.Shinya YamanakaCell 2007Induction of Pluripotent Stem Cells from Adult Human Fibroblasts by Defined FactorsOct4/Sox2/Myc/Klf4干细胞基础研究的重大问题自我复制（Self-renewal）和多分化潜能(Pluripotency)的维持胚胎干细胞向各种组织的功能细胞的分化调控干细胞基因组重编程的机制(SCNT

57、，iPS cells)肿瘤干细胞肿瘤细胞是否由干细胞变异而来？肿瘤对治疗的耐受是否由于存在肿瘤干细胞6.1 单克隆抗体单克隆抗体 1975 1975年英国科学家年英国科学家Milstein和和Kohler将产生抗体将产生抗体 的淋巴细胞同肿瘤细胞融合，成功建立了单克隆抗的淋巴细胞同肿瘤细胞融合，成功建立了单克隆抗 体技术，而获得体技术，而获得1984年诺贝尔医学和生理学奖。年诺贝尔医学和生理学奖。 每个每个B淋巴细胞仅专一地产生、分泌一种针对某淋巴细胞仅专一地产生、分泌一种针对某 种抗原决定簇的特异性抗体，而肿瘤细胞可以无限种抗原决定簇的特异性抗体，而肿瘤细胞可以无限 增殖，因此杂交瘤细胞可在

58、体外培养或移植到体内增殖，因此杂交瘤细胞可在体外培养或移植到体内 条件下分泌大量单克隆抗体。条件下分泌大量单克隆抗体。 单克隆抗体技术的最主要优点是可以用不纯的抗单克隆抗体技术的最主要优点是可以用不纯的抗 原分子大量制备纯一的单克隆抗体。原分子大量制备纯一的单克隆抗体。杂交瘤细胞产生杂交瘤细胞产生 单克隆抗体示意图单克隆抗体示意图6.2 动物克隆动物克隆 生物繁殖后代通常是以精、卵细胞结合的有性生殖生物繁殖后代通常是以精、卵细胞结合的有性生殖方式进行。通过营养体细胞繁殖个体的方法称为无性繁方式进行。通过营养体细胞繁殖个体的方法称为无性繁殖。克隆是指离体条件下的无性繁殖。殖。克隆是指离体条件下的

59、无性繁殖。1981年年Illmenses 率先报告用小鼠幼胚细胞核克隆出正常小鼠。随后，率先报告用小鼠幼胚细胞核克隆出正常小鼠。随后，1984年年Willadsen用未成熟羊胚细胞核克隆出一头羊。用未成熟羊胚细胞核克隆出一头羊。 英国英国PPI生物技术的罗斯林（生物技术的罗斯林（Roslin）研究所的维尔）研究所的维尔穆特穆特(Wilmut)博士博士1997年年2月月27日在世界著名权威杂志日在世界著名权威杂志Nature宣布的用乳腺细胞的细胞核克隆出一只绵羊宣布的用乳腺细胞的细胞核克隆出一只绵羊“ 多莉多莉 (Dolly) ”的消息。的消息。“多莉多莉”的诞生，既说明了体细的诞生，既说明了体

60、细胞核的遗传全能性，也翻开了人类以体细胞核竞相克隆胞核的遗传全能性，也翻开了人类以体细胞核竞相克隆哺乳动物的新篇章。此项技术因而荣登美国哺乳动物的新篇章。此项技术因而荣登美国Science周刊评出的周刊评出的1997 年十大科学发现年十大科学发现 的榜首。的榜首。 绵羊绵羊B乳腺细胞核乳腺细胞核易核卵易核卵融合卵融合卵绵羊绵羊C子宫子宫多莉多莉植入植入植入植入生产生产克克隆隆多多莉莉羊羊示示意意图图取出取出未受精卵未受精卵去核去核电激电激体外胚胎发育体外胚胎发育绵羊绵羊A多莉多莉克隆猴克隆猴 (1)遗传素质完全一致的克隆动物将更有利于开展对动遗传素质完全一致的克隆动物将更有利于开展对动物物(人