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1、Cloning從複製羊到複製人Yu-HuiTsaiPh.D.台北醫學大學醫學科學研究所蔡郁惠CellDifferentiation (細胞分化)Inthefieldofbiologicalsciences,thereisadogmathattheexpressionstateofgenomeindifferentiatedcellsduringthecourseofdevelopment,especiallyintheterminaldifferentiatedcells,isirreversible.CloningPlantsfro
2、maSingleCellInplants,theabilityofadifferentiatedcelltodevelopintoawholenewindividualiscommon.Asinglecellremovedfromcarrotrootandplacedinculturemediummaybegindividingandeventuallygrowintoanadultplant.Inthisway,itispossibletopropagate/clonelargenumberofplantshavingdesirabletraits
3、.Basedonthisdata,itisevidentthatdifferentiationdoesnotnecessarilycauseirreversiblechangesingenomicDNA.ChimericembryoWhatisCloning?ScientificAmerican(2002):p.18-19WhatisCloning?Cloningisa(new)biotechnologicalprocessinvolvinginjectingadiploidnucleusintoanunfertilized,enucleatedeg
4、gandallowittodevelopuptoblastocytesoralivenewborn.Cloningmaybesubdividedinto:Therapeuticcloning:toproducestemcellsforregenerativemedicineReproductivecloning:tocreateabodyFrogIn1952,AmericanembryologistsRobertBriggsandThomasKingperformednuclear-transferexperimentswithfrog.Theyfo
5、undthatthenumberofembryossurvivingtobecometadpoleswassmallerwhendonorcellsweretakenfromanimalsatamoreadvanceddevelopmentalstage.Only1to2percentofembryossurvivedtobecomeliveoffspring.Someofthoseclonesthatsurvivethroughbirthdieshortlyafterward.CloningformedicineScientificAmerican
6、(1998):p.58-63MeganandMorage: clonesofembryoniccellsIn1995,ScientistsatRoslinInstitutenearEdinburgh,Scotland,managedtoproduceMeganandMoragefromculturedcellsderivedfromanine-day-oldembryo.ThismadeMeganandMorageclonesoftheembryo.Thus,partiallydifferentiatedcellscanbegeneticallyre
7、programmedtofunctionlikethoseinanearlyembryo.ClonesfromcellsofamaturedanimalInFebruary1997,Dollywasthefirstmammalclonedfromacellofmaturedewe’s.GenetictestsprovethatDollyisacloneoffullydifferentiatedmammarycellofanadult.Allclonedoffspringlooklikethebreedofsheepthatdonatednucleus
8、.DollygivebirthtoBonnie,whichisnormal,in1998.Later,Bon
