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2. Phi phn chia nhiu ln v c dng khi cu c gi l phi nang/phi bo. (3) 5 To 7 Days : 5 n 7 Ngy Vo thi im ny, t bo gc phi c th quan st c v c kh nng pht trin thnh bt k loi t bo no ca c th. (4) Stem Line : Dng T Bo Gc T bo gc c tch ra v pht trin trong a nui cy. Khi chng phn chia chng to ra dng t bo gc. (5) Tissue Production : Sn Xut T Bo p dng nhiu cng thc dinh dng phi hp vi cc yu t khc nhau, cc nh khoa hc hy vng c th bin i t bo gc thnh hn 200 loi t bo khc ca c th nh: Pancreatic Islet Cells : T Bo Ty Tng - C th s dng iu tr tiu ng Muscle Cells : T Bo C - C th dng khi phc hoc thay th tim b tn thng Nerve Cells : T Bo Thn Kinh - C th c ng dng trong iu tr chng mt tr v bnh Parkinson cng nh iu tr chn thng ct sng.T nhng nm 1980, cc nh khoa hc tch chit thnh cng t bo gc phi cachut. Nhng ch n nm 1998, mt nhm cc nh khoa hc thuc i hcWinsconsin ti Madison di s ch o ca gio s James Thomson ln u tin thnh cng tch bit t bo gc phi ngi. H bit h tch c t bo gc,l v nhng t bo khng bit ha trong khong thi gian di; chng cng vngi nguyn kh nng c th bin i thnh nhiu loi t bo chuyn bit trong c t bo c, t bo rut, t bo thn kinh v t bo sn. Nh sinh hc kim gio s ngnh gii phu hc, Prof. James Thomson ngng lm vic vi chic laptop computer trong vn phng ti i hc Wisconsin - Madison. ng ch o nhm nghin cu v tuyn b tch thnh cng dng t bo phi ca mt loi ng vt linh trng vo nm 1995. Khi u ny em n thnh tu ln u tin tch c dng t bo gc phi ngi vo nm 1998. 3. The Promise of Stem Cell Research : Trin vng ca nghin cu t bo gc Drug Development and Toxicity Tests : Nghin cu dc phm v xt nghim c tnh Experiments to Study Development and Gene Control : Th nghim nhm pht trin nghin cu v kim sot gen Cultured Pluripotent Stem Cells : T bo gc ton nng ang c nui dng Tissues/Cells for Therapy : T bo ng dng trong iu tr Bone marrow : Ty xng Nerve Cells : T bo thn kinh Heart Muscle Cells : T bo c tim Pancreatic Islet Cells : T bo ty tngV th l nghin cu t bo gc c nhiu nh khoa hc eo ui vi hy vng tc nhng bc t ph ln trong y hc. H lun n lc tm ti nhng liuphp khi phc hoc thay th cc t bo tn thng nh nhng t bo to ra t tbo gc; ng thi mang hy vng n cho nhng ngi ang phi chu ng cnbnh ung th, tiu ng, cc bnh tim mch, chn thng ct sng cng nh ccchng ri lon khc. C t bo gc phi v t bo gc trng thnh u l nhngc s cc nh khoa hc pht trin nhng phng thc mi, c gi tr nhm snxut dc phm v xt nghim.The Promise of Stem Cell Research :Trin vng ca nghin cu t bo gcCultured Pluripotent Stem Cells :T bo gc ton nng ang c nui dngIdentify drug targets and test protential therapeutics :Xc nh mc tiu dc phm v th nghim tim nng liu php iu trToxicity Testing : Xt nghim c tnh 4. Study Cell differentiation : Nghin cu qu trnh bit ha ca t boTissues/Cells for Transplantation : T bo ng dng trong cy ghpUnderstanding, prevention and treatment of birth defects :Tm hiu, phng nga v iu tr khim khuyt bm sinhBone marrow for leukemia & chemotherapy :Ty xng sn xut bch cu v ng dng trong ha hc tr liuNerve Cells for Parkinsons & Alzhiemers disease :T bo thn kinh ng dng trong iu tr chng mt tr v bnh ParkinsonHeart Muscle Cells for heart disease :T bo c tim ng dng trong iu tr bnh timPancreatic Islet Cells for diabetes :T bo ty tng gip iu tr tiu ngT bo gc cng l cng c hu hiu gip tin hnh cc nghin cu sinh hc c s,nhm c c nhng hiu bit su sc hn v c th ngi. Nh vo cc chuyngia khoa hc, bc s, cc chuyn gia o c sinh hc v nhng ngi khc na, cChnh ph cng vi Gio hi nghin cu tim nng ca k thut t bo gctrong y hc, ng thi lp nn mt din n tho lun ngha o c cng nhnhng vng mc v mt o c trong vic nghin cu t bo gc.I. KHI QUT V T BO GCT bo gc l mt trong nhng lnh vc sinh hc li cun nht hin nay. Nhngcng ging nh rt nhiu lnh vc khoa hc ang ln mnh, nghin cu v t bogc lm ny sinh nhng cu hi v c mt khoa hc ln mt o c ngay khi nt c nhng thnh tu u tin.1. T BO GC L G V TI SAO T BO GC LI QUAN TRNG ?T bo gc l t bo nn mng ca tt c cc t bo, m v c quan trong c th.V c bn, mi t bo trong c th ngi u c ngun gc t trng th tinh(cn c gi l hp t) - chnh l s kt hp gia tinh trng v trng. 5. Fertilised egg : Trng th tinhTotipotent stem cells : T bo gc tng nng (2)Blastocyst containing pluripotent stem cells :Phi nang cha t bo gc ton nng (3)Isolated pluripotent SCs from inner cell mass :T bo gc ton nng c tch ra t khi t bo ni tiHematopoeitic SCs : T bo gc muNeural SCs : T bo gc thn kinhMesenchymal SCs : T bo gc trung mTissue-specific SCs : T bo gc chuyn mCultured pluripotent SCs : T bo gc ton nng c nui cyBlood cells : T bo muCells of nervous system :T bo thn kinhConnective tissue: bones, cartilage, etc.: M lin kt: xng, snNhng c th chng ta c n hn 200 loi t bo khc nhau, ch khng phi chmt loi duy nht. Tt c nhng loi t bo ny u hnh thnh t mt vn t bo 6. gc giai on pht trin sm nht ca phi. Trong giai on ny, cng nh giaion pht trin sau , cc loi t bo gc hnh thnh nn t bo chuyn bit haybit ha ri thc hin cc chc nng c th trong c th ngi; v d nh tbo da, t bo mu, t bo c v t bo thn kinh.T bo gc c mt kh nng v song, l chng c th pht trin thnh nhiu loit bo khc trong c th. ng vai tr l h thng sa li cho c th, v mt lthuyt, chng c th phn chia khng hn nh thay th cc t bo khc, v ngthi m bo s lng cc loi t bo trong c th, min l con ngi hay con vtcn sng. Khi mt t bo gc phn chia, mi mt t bo mi va c kh nng trthnh t bo gc va c th tr thnh mt loi t bo khc vi chc nng chuynbit nh t bo c, t bo hng cu hay t bo no.Cell Differentiation - Qu trnh bit ha t boSkin cells of epidermis : T bo biu bNeuron of Brain : Nron trong noPigment Cell : T bo sc tEctoderm (External Layer): Ngoi b (lp ngoi)Sperm : Tinh trngEgg : TrngGerm Cells : Giao t 7. Zygote : Hp tBlastocyst : Phi boGastrula : Phi dMesoderm (Middle Layer): Trung b (Lp gia)Cardiac Muscle : C timSkeletal Muscle Cells : T bo c xngTubule Cell of the Kdney : T bo ng trong thnRed Blood Cells : T bo hng cuSmooth Muscle (in Gut): T bo c trn (trong rut)Endoderm (Internal Layer): Ni b (lp trong cng)Lung Cell (Alveolar Cell): T bo phi (T bo ti phi)Thyroid Cell : T bo tuyn gipPancreatic Cell : T bo ty tngQU TRNH PHN CHIA V BIT HA T BOTt c cc loi t bo gc, d bt ngun t u, cng u c 3 c tnh chung:chng c kh nng phn chia v t ti to trong khong thi gian di; chng khngb bit ha; v chng c th pht trin thnh cc loi t bo chuyn bit. iukin thch hp, t bo gc c th pht trin thnh cc m v c quan chuyn bit.Nhng c tnh c nht v nh ny l yu t ha hn, khin t bo gc tr thnhngun cung cp t bo, nhm iu tr cc chng bnh nh chng mt tr nh, ungth, bnh Parkinson, tiu ng loi 1, chn thng ct sng, t qu, bng, bnhtim, vim khp xng mn tnh v vim khp dng thp. Ngy nay, cc m hay cquan b bnh, b hy hoi u c thay th t ngi hin tng. V c bn, slng ngi cn cy ghp vt xa s lng b phn thay th sn c. T bo gcchnh l ngun tim nng cung cp cc t bo v m c th c ng dng trongiu tr nhiu cn bnh, do t bo gc c th t phc hi v to ra cc t bochuyn bit.Nh bi chnh c tnh ny ca t bo gc khin cc nh khoa hc say m nghincu hu tm kim cc bin php iu tr y hc nhm thay th cc t bo b hyhoi hoc thng tn.II. NGHIN CU T BO GC1. T bo gc bt ngun t u? 8. 1. Fertilization : S th tinh2. 8-Cell embryo : Phi gm c 8 t bo. Trong giai on pht trin ny, t bo gcphi c coi l t bo gc tng nng (Totipotent stem cells); mi t bo ny ctim nng pht trin thnh mt con ngi.3. Blastocyst : Phi bo. Trong giai on pht trin ny, t bo gc phi c coi lt bo gc ton nng (Pluripotent stem cells); mi t bo ny c tim nng pht trinthnh bt k t bo no trong c th.4. Fetus : Bo thai. Trong giai on pht trin ny, t bo gc phi c coi l tbo gc ton nng (Pluripotent stem cells); mi t bo ny c tim nng pht trinthnh bt k t bo no trong c th.5. T bo gc cng tm thy ni c th trng thnh. Chng duy tr v cha tr cth. Chng c nh v ti nhiu t bo trong c th. Cc t bo gc trng thnhc tim nng nhn ly nhng tnh cht ring bit, hu c th to nn cc t bo cs lng hn nh trong cc m. Chng c coi nh l cc t bo gc a nng(Multipotent stem cells).Tt c chng ta u khi u s sng t mt t bo duy nht, gi l hp t, hnhthnh sau qu trnh th tinh. Hp t phn chia to thnh hai t bo; mi mt t botrong li phn chia v c tip din nh vy. Chng my chc, khong 5 ngysau khi th tinh, hp t c dng mt qu bng rng, vi khong 150 t bo cgi l phi bo (blastocyst). Phi bo thm ch cn nh hn mt ht ct, bao gm 2nhm t bo: nguyn bo nui phi (trophoblast) v khi t bo ni ti trong phibo. T bo gc phi l nhng t bo hnh thnh nn khi t bo ni ti (inner cellmass). Do t bo gc phi c th hnh thnh, nn bt c loi t bo no trong cth ngi trng thnh nn n cn c coi l t bo gc ton nng (pluripotentstem cell). 9. T bo gc cng c th tm thy mt s loi m nht nh ngi pht trinton din, t tr em n ngi trng thnh, vi s lng rt t. V d, t bo gcty xng (t bo gc mu) c trong ty ca xng, chng pht trin thnh tt ccc loi t bo mu chuyn bit.QU TRNH BIT HA T BO GC TY XNGLiver : GanBrain : NoCNS stem cells : T bo gc CNSSkeletal muscle : C xngBone : XngBlood cell : T bo muBlood vessel : Mch muBone marrow stromal cell : t bo m ty xngEpithelial cell : T bo biu mNeuron : NronGlial cell : T bo thn kinh mFat cell : T bo m mCardiac muscle : C timT bo gc trng thnh c lp trnh cch c trng hnh thnh nn cc loit bo khc nhau cho m ca chng. Nhng t bo ny c gi l t bo gc anng (multipotent stem cells). Hin nay cc khoa hc gia vn cha xc nh cht mi t bo gc trng thnh trong cc c quan quan trng ca c th. Mt sm nh no, mc d c t bo gc tn ti nhng chng li khng hot ng, do 10. chng khng sn sng phn ng vi t bo b chn thng hay tn hi. Hin thicc nh khoa hc cng ang tm kim cch thc kch thch nhng t bo gc anghin din chng pht trin v to ra ng loi t bo cn thit nhm thay th tbo b hy hoi.T BO GC CNG C TH THU HOCH C T NHNG NGUNNH DY RN, NHAU THAI CA TR S SINHFig. 1: The Umbilical CordHnh 1: Dy rnFig. 1 : The Amniotic FluidHnh 2 : Nc iHnh 1 v 2: T bo gc cng c th thu hoch c t nhng ngun nh dy rn,dch i hay nhau thai ca tr s sinh.y l ngun t bo gc c th tip cn c, so vi m no hay ty xngtrng thnh. Mc d cc nh khoa hc c th to nhng t bo ny trn a nuicy nhng rt gii hn. Mi y, cc nh khoa hc khm ph s tn ti ca tbo gc trong rng sa ca tr em v nc i bao xung quanh thai nhi. Nhng tbo ny cng c th c tim nng hnh thnh nn nhiu loi t bo khc. Nghin 11. cu tm hiu c im nhng t bo ny rt ha hn, nhng mi ch c thchin giai on u.2. Cc loi t bo gcTrong c th mi chng ta u c cha t bo gc, t nhng giai on pht trinu tin cho n cui cuc i.V c bn c 3 loi t bo gc: t bo gc tng nng, t bo gc ton nng v tbo gc a nng. Loi t bo gc M tV d Mi t bo c th pht trin T bo phi giai on mi pht T bo gc tng nng thnh mt c trin (t 1 n 3 ngy) th mi T bo c th hnh thnh nn bt c loi t T bo gc phi tm thy phi bo T bo gc ton nng bo no trong(t 5 n 14 ngy) c th (trn 200 loi) T bo c bit ha, nhng vn c th hnh M bo thai, mu dy rn v t boT bo gc a nng thnh nn mt gc trng thnh s loi t bo khcTt c cc t bo gc u c ch trong nghin cu y hc, nhng mi loi u c ctrin vng cng nh gii hn ring. T bo gc phi c hnh thnh t rt smtrong qu trnh pht trin ca con ngi, v d nh phi bo, c tim nng to ra ttc cc loi t bo ca c th. T bo gc trng thnh ch c trong nhng loi mnht nh ngi pht trin ton din, t tr em thnh ngi ln, ch gii hnto ra mt s loi t bo chuyn bit nht nh m thi.CC NGUN KHC BIT CA T BO GC 12. Embryonic stem cells : T bo gc phiEarly human embryo at blastocyst stage :Phi ngi giai on phi boAdult stem cells : T bo gc trng thnhFrom bone marrow in this example : Ly t ty xngTotipotent cells : T bo gc tng nngPluripotent cells : T bo gc ton nngCultured stem cells : T bo gc c nui cyDifferent culture conditions : iu kin nui cy khc nhauDifferent types of differentiated cells :Cc loi t bo bit ha khc nhauLiver cells : T bo ganNerve cells : T bo thn kinhBlood cells : T bo mu3. T BO GC PHI L G ?T bo gc phi c th c to ra t qu trnh th tinh trong ng nghim (IVF).T bo gc phi khi ngun t nhng t bo to nn khi t bo ni ti trong phibo. T bo gc phi chut c kh nng to ra bt c loi t bo no trong c thdi iu kin thch hp. Do , t bo gc phi c coi l t bo ton nng, ckh nng phn chia khng hn nh cho n khi sinh trng v bit ha. T bo gcphn chia lin tip trong mi trng nui cy m trong lng p, nhng cng lc duytr kh nng hnh thnh nn loi t bo khc khi c t trong mi trng thchhp thc y qu trnh bit ha. 13. Stem Cells From In Vitro Fertilization (IVF) :T bo gc ly t qu trnh th tinh trong ng nghimUnused, frozen embryo slated to be thrown away :Phi khng s dng v ng lnh b sa thiPluripotent stem cells : T bo gc ton nngPancreactic (islet cells) : t bo ty tngHematopoietic (blood cells) : t bo muCardiomyocytes (heart cells) : t bo timNeurons (brain cells) : NronHepatocytes (liver cells) : t bo ganCc mu t bo gc phi ngi hin ang c nghin cu. Mt vi nhm nghincu ang tm hiu liu t bo gc phi ngi c s hu cng nhng c tnh gingt bo gc phi chut hay khng. Do t bo gc phi ngi ch mi c tch trongthi gian gn y, do vn hiu bit ca chng ta cn hn ch v cch thc phnchia ni t bo gc. Tin hnh nghin cu trn h thng c th con ngi cng khkhn hn so vi chut. Tuy nhin, cc nh nghin cu v ang t c nhngtin b ng k, hu c th tm ra nhng liu php nhm thay th hoc khi phccc m b hy hoi, trong vic s dng nhng t bo gc ny.T bo gc phi ngi cn c th c thu hoch nh k thut chuyn nhn(nuclear transfer). K thut chuyn nhn t bo, t d t bo da cng l mt 14. phng thc c tim nng to ra t bo gc phi.How cloning might be used therapeutically : - K thut nhn bn v tnh cng dng trong iu tr bnh nh th no?Anucleate unfertilized egg from donor :Trng hin tng cha th tinh c tch nhnNucleus Transfer : Chuyn nhn t boAdult cell from patient : T bo trng thnh ca ngi bnh loi vt, k thut chuyn nhn c thc hin bng cch ghp nhn ca t botrng thnh bit ha, v d t bo da chng hn, vo trng tch nhn. Trng c cha cht liu di truyn ca t bo da, sau c kch thch hnh thnhphi bo, ri sau c th thu hoch t bo gc phi. Nhng t bo gc c tora theo cch ny l nhng bn sao hay phin bn v tnh ca t bo trng thnhban u do ADN (4) trong nhn ca chng ging vi ADN ca t bo trng thnh.Cho n ma h nm 2006, k thut chuyn nhn vn cha thnh cng, nhm tot bo gc phi ngi, nhng cc tin b t c trn nghin cu ng vt cho tahy vng rng cc khoa hc gia c th s dng k thut chuyn nhn ny trong victo ra t bo gc ngi trong tng lai.3. T BO GC PHI L G ?T bo gc trng thnh rt khc vi nhng t bo tch ra t phi hay bo thai vc cc m pht trin, v d nh loi vt hay ngi sau khi c sinh ra. Cth tch nhng t bo ny t rt nhiu m hoc c quan, trong bao gm c no.Tuy nhin ni ph bin nht c th thu hoch chng l t ty xng nm ngaychnh gia cc ng xng.Vic nghin cu v th nghim trn t bo gc trng thnh, gn y gy cnhiu s ch . Cc nh khoa hc pht hin s hin din ca t bo gc trngthnh nhiu m, so vi nhng g m h hiu bit trc y. V d, t bo gcmu thng thng ch sn xut cc loi t bo mu khc nhau. Tuy nhin nghincu gn y li cho thy mt s t bo gc trng thnh c th d dng thch nghihn so vi cc quan nim trc y. T bo gc trng thnh tch t chut (trng 15. thnh) c th pht trin thnh t bo da, c v gan. Pht hin ny khin cc nhkhoa hc t ra cu hi liu t bo gc trng thnh c th c s dng cyghp hay khng. Mc d kt qu vn cha c chng minh cng nh cha cthc hin vi t bo ngi. Tuy nhin, cc nh khoa hc vn ang n lc tm kimmt phng php kch thch t bo gc trng thnh, hay thm ch l nhng loi tbo trng thnh khc, chng tr nn linh hot hn. Nu thnh cng, phngphp s cung cp thm mt ngun t bo gc cha bit ha.Hn na, gn y mt gi thuyt v "s bit ha t bo gc" a ra lun imrng, mt s t bo gc trng thnh c th c tim nng to ra cc loi t bokhc, nhiu hn nhng g mi ngi vn ngh trc y. iu ny c ngha l tbo gc trong ty xng, ban u c cho l nhng t bo ch to ra mu, c thgp phn vo vic ti sinh v s h hi ca gan, thn, tim, phi v cc c quan bhy hoi khc. Nu c th kim sot qu trnh bit ha ca t bo gc trngthnh trong phng th nghim, nhng t bo ny c th tr thnh nn tng chonhng liu php iu tr nhiu cn bnh nan y.Trong nhng nm va qua, vic nghin cu trong lnh vc t bo gc trng thnh pht trin vt bc. T bo gc trng thnh c th c phc hi bi cc mly t bnh nhn, nui dng trong cc da cy v kch thch pht trin thnhnhiu loi t bo trng thnh. Vic s dng t bo gc cho phng php tr liu,thay v dng t bo gc phi, c nhiu thun li v mang mt ngha quan trngi vi lnh vc khoa hc, lun l v chnh tri.To t bo gc t chnh m ca bnh nhn c th loi b hon ton vn hthng min nhim (min dch) khng chp nhn.1. T bo da c ly t phn bng ca bn nhn. Nhn c cha DNA (cu t cbn di truyn) ca ngi bnh c ly t t bo da.2. Nhn ca t bo ngi bnh c cy vo t bo trng cha th tinh, sau khinhn ca trng c tch ra khi3. T bo trng sinh sn (theo cp s nhn bi) v to nn cc t bo gc.4. Cc t bo gc c chuyn sang mt da nui cy chng c th pht trinthnh nhng loi t bo m bnh nhn cn cha tr cn bnh ca ng ta, t dnh gan, thn kinh, tim, t bo insulin. 16. 5. Cc t bo c tim vo cho bnh nhn, hu iu tr cn bnh cho bnh nhn.C th ngi bnh s khng o thi cc t bo ny, bi v chng cha DNA cang ta (ngha l cc t bo u c chung mt loi DNA ging nhau, l hthng min dch s chp nhn).T bo gc trng thnh khng gy ra khi u c qui (teratomas).ng dng t bogc trng thnh trong iu tr gp phi rt t nhng vn v lun l v cnghon ton trnh c nhng tranh lun nng bng v chnh tr, lin quan n vics dng phi ngi. (5)Mc d lnh vc ny c bit hp dn, nhng n cng gy nhiu tranh ci trongcng ng khoa hc v ng thi cn c thm nhiu nghin cu b sung k lng hiu c ton b tim nng ca t bo gc trng thnh, c bit l so vi tbo gc phi.Trong bi vit k tip, tc ga s cp n tim nng s dng t bo gc - baogm t bo gc phi v t bo gc trng thnh - trong y khoa tr liu. ng thicng nu ln mt s vn nn v mt lun l, nu chng ta chp nhn cho cc khoahc gia c php s dng cc phi thng d hoc to nn cc phi mi bngphng php nhn bn v tnh v s dng cc phi y nh l nguyn liu sng,hon ton cho mc ch nghin cu.Hon chnh bn dch Lm Trn Mnh HngCopyright 2008 by Trn Mnh HngL.J. Goody Bioethics Centre39 Jugan Street, Glendalough, WA. 6016. AUSTRLIA.Email: [email protected] thch :(1) Thut ng "t bo gc" ch tt c nhng t bo cha bit ha c kh nngphn chia thnh bt c loi t bo no. T bo gc sn sinh ra mt cp t bo con(daughter cells), trong mt t bo s pht trin bit ha, t bo cn li phttrin thnh t bo gc mi thay th t bo gc ban u. Thut ng "gc" ch rarng nhng t bo ny l ngun gc ca cc t bo chuyn bit khc. Trong c thc rt nhiu t bo gc cc giai on pht trin khc nhau. V d, tt c cc tbo no u c to ra t mt nhm t bo thn kinh gc. Mi mt t bo thnkinh gc li sinh ra mt t bo no v mt bn sao ca chnh n trong mi ln phnchia. Nhng t bo gc u tin l nhng t bo c sinh ra trong ln phn chiath nht ca trng th tinh c gi l t bo gc phi, nhm phn bit chngvi cc nhm t bo hnh thnh sau cc m c th (nh t bo thn kinh gc).Nhng t bo gc phi (trong giai on u tin) pht trin thnh tt c cc loi mtrong c th, v th chng c t cho ci tn "t bo ton nng" c th to ra miloi t bo.(2) Totipotent Stem Cells: T bo gc tng nng. Loi t bo ny pht trin sau khitrng c th tinh khong 3-4 ngy, chng hin din phi du (morula). Nu 17. cc chuyn gia tch mt trong cc t bo ny v cy vo t cung ca ngi ph nthnh cng. T bo tng nng ny s pht trin thnh mt thai nhi.(3) Pluripotent Stem Cells: T bo gc ton nng. Chng ch c kh nng pht trinthnh bt k t bo no trong c th, gm cc t bo c cc chc nng chuyn bit.Tuy nhin, chng khng c kh nng pht trin thnh mt hu th nh l t bogc tng nng (Totipotent Stem Cells).(4) ADN vit tt ca cm t - Acid Deoxyribonucleic. The genetic material found inall living things; contains the inherited characteristics of every living organism - Cut c bn di truyn.(5) Xem Maureen L. Condic, "The Basics About Stem Cells," First Things (January2002).http://www.firstthings.com/article.php3?id_article=1959