干细胞之家 - 中国干细胞行业门户第一站

 

 

搜索
朗日生物

免疫细胞治疗专区

欢迎关注干细胞微信公众号

  
查看: 9385|回复: 0
go

Cloning Yields Human-Rabbit Hybrid Embryo [复制链接]

Rank: 7Rank: 7Rank: 7

积分
97 
威望
97  
包包
3142  
楼主
发表于 2008-12-31 00:33 |显示全部帖子 |倒序浏览 |打印
日期: 2003-08-14 今日/总浏览: 1/475
# k! Q+ w: w9 v: w0 g* b8 U9 s, s! y+ S0 c! a, y: l

+ `4 F: a% X7 C4 j4 ~5 _1 T& q3 z! k& r* i& l& m0 l

% e9 |) U* e6 d. J* bScientistsinChinahave,forthefirsttime,usedcloningtechniquestocreatehybridembryosthatcontainamixofDNAfrombothhumansandrabbits,accordingtoareportinascientificjournalthathasreignitedthesmolderingethicsdebateovercloningresearch.8 j5 Y6 b7 N- F' E( |- Y  @& F
3 k5 X9 _& t: D5 H. S8 [5 A8 m& W
Morethan100ofthehybrids,madebyfusinghumanskincellswithrabbiteggs,wereallowedtodevelopinlaboratorydishesforseveraldaysbeforethescientistsdestroyedthemtoretrieveso-calledembryonicstemcellsfromtheirinteriors.AlthoughscientistsinMassachusettshadpreviouslymixedhumancellsandcoweggsinasimilarattempttomakehybridembryosasasourceofstemcells,thoseexperimentswerenotsuccessful.* q* e9 Q1 {. _$ z" B
7 T' f: o0 r8 Q: P5 L+ q# x+ a
Researcherssaidyesterdaytheywerehopefulthattherabbitworkwouldleadtoanewandplentifulsourceofembryonicstemcellsforresearchand,eventually,formedicaluse.Buttheologiansandothersdecriedtheworkasunethical.
6 V% X: Y8 W( [. U
1 |; s6 E& n9 G9 r5 x+ T1 ASomewonderedaloudwhat,exactly,suchacreaturewouldbeifitweretransferredtoawombtodeveloptoterm.6 H" M7 W$ I( `5 F* v3 ]  ~, o

( P1 ?- c; Y7 s: B# X3 C, yThevastmajorityoftheDNAintheembryosishuman,withasmallpercentageofgeneticmaterial--calledmitochondrialDNA--contributedbytherabbitegg.Nooneknowsifsuchanembryocoulddevelopintoaviablefetus,thoughsomeexperimentswithotherspeciessuggestitwouldnot.0 I4 s% [5 H" F( H+ b& t

2 B8 `' K( E+ D! Z; \8 I0 gCongresshasbeenmullinglegislationforyearsthatwouldoutlawcertainhumancloningexperiments,withsomeopposedtoanycreationofclonedembryosforresearchandotherssympathetictoresearchusesaslongastheembryosarenotallowedtogrowintoclonedbabies.Nolawhasbeenpassed,however,inpartbecauseofresearchers'warningsthattheproposedrestrictionsaresofar-reachingthattheywouldhobbledevelopmentofnewmedicaltreatments.0 H) ~+ c6 }6 X# P. F

: Q+ V3 x1 o& p9 v' ?- c& n% x: jThenewwork,ledbyHuiZhenShengofShanghaiSecondMedicalUniversity,appearsinthelatestissueofCellResearchandwashighlightedinanewsreportinthejournalNature.CellResearchisapeer-reviewed--iflittle-knownintheUnitedStates--bimonthlyscientificjournalaffiliatedwiththeShanghaiInstituteofCellBiologyandtheChineseAcademyofSciences.Someresearchersyesterdaysaidtheywerefrustratedbythelackofdetailsinthepaper.& C  j5 W: j5 [& D  q5 F( y

. p: h3 V$ u) A: _9 a% tTheteamsaiditretrievedforeskintissuefromtwo5-year-oldboysandtwomen,andfacialtissuefroma60-year-oldwoman,asasourceofskincells.TheyfusedthosecellswithNewZealandrabbiteggsfromwhichthevastmajorityofrabbitDNAhadbeenremoved.Morethan400ofthosenew,fusedentitiesgrewintoearlyembryos,andmorethan100survivedtotheblastocyststage--thepointatwhichcovetedstemcellsbegintoform.
7 h6 Y# ]0 j; ^+ f! F
7 r4 @+ N& _& D% P4 yTheapproachcouldhelpscientistswishingtomass-producehumanembryosassourcesofhumanembryonicstemcells.Stemcellscanmorphintoallkindsoftissuesandmaybeabletoreversetheeffectsofvariousdegenerativediseases.Buttomakeclonedembryos,scientistsneedbothnormalbodycells--suchasskincells--andeggcells,whichhavetheuniquecapacitytoreprogramthegenesinbodycellsandmakethembehaveasthoughtheywereembryocells.
# s8 U1 s5 ^: l" P9 W" G; \: m. i  P; E# Y* @1 l
Becausehumaneggcellsaredifficultandcostlytoretrievefromwomen'sovaries--andbecausehumaneggretrievalposesriskstothedonors--scientistshavebeenwantingtoknowwhetheranimaleggsmayserveaswell.AmajorquestionhasbeenwhethertheremnantsofmitochondrialDNAthattypicallyremaininananimaleggwouldbecompatiblewiththenuclearDNAcontributedbythehumancell.9 W* F5 v; M- a
9 u4 P: v! N6 {- x
Thenewworksuggeststhattheanswertothatquestionisyes,scientistssaid--thoughwithanumberofcaveats.Mostimportant,researcherssaid,thepaperstopsshortofprovingbeyondadoubtthatthestemcellsretrievedfromthehybridembryosaretrulycapableofgrowingforlongperiodsoftimeinlabdishes,andthattheycanturnintoeveryknownkindofcell.
8 j7 Y' f/ D6 v, y5 U; J, y% ^7 M- I' W/ z
Evenso,saidDouglasMelton,aHarvardUniversitycellbiologistandcloningexpert,theworkisabigadvancebecauseitoffersanewsystemforexploringthemechanismsbywhicheggcellsgetadultcellstoactinembryonicways.Thatcouldprovidedeepinsightsintohumandevelopment,woundhealingandtissueregeneration.
! m. q7 V1 Y! j2 Q2 p+ v. r6 V/ G# M
Henotedthatalthoughthisisthefirstcreationofahumanchimericembryo--areferencetothefabulouschimeraofGreekmythology,whichhadalion'shead,agoat'sbodyandaserpent'stail--itisnotthefirsttimescientistshaveblendedhumancellsintolabanimals.Somemice,forexample,havebeenendowedwithhumanbraincellsorportionsofthehumanimmunesystemforresearch.# }' v) ]5 ]: ]  z
6 v  |3 j' P( M  L. J8 E1 {$ ^
TheChinesework,Meltonsaid,isextremelyinteresting,andIhopetheypursueit.# A4 Z+ K$ h0 {" W$ f; C

, t. o8 v6 X' T1 ^7 BR.AltaCharo,anassociatedeanoflawandprofessorofbioethicsattheUniversityofWisconsinatMadison,notedthattheworkpassedmusterwithChineseethicsauthorities,whohaddemanded,amongotherthings,thattheembryosnotbeallowedtogrowmorethan14days.6 u% S1 r( c9 c: Q" V
! r* e7 b+ z" W& F: a4 m9 @
Shortofputtingoneoftheseembryosintoawoman'sbodyfordevelopmenttoterm,Idon'tthinkthisworkharmsanyonealive,Charosaid.
- A4 e: L5 s3 b  i
! `% E( F* k  U+ rShesaidtheexperimentsshouldforceopponentsofcloningresearchtoidentifymoreclearlythantheyhaveuntilnowexactlywheretheywoulddrawthelineagainsthumanembryocloning--ineffect:Howhumandoesanembryohavetobetohavethemoralstandingtheseadvocatesconferonembryos?$ N+ Y  m% H9 B% W; [  j1 x: H& T
( f- t) Z) F$ D% J  s- F% g
RichardDoerflinger,oftheU.S.ConferenceofCatholicBishops,saidhefeltcertainthatthehuman-rabbitembryoswerehumanenoughtodeserveprotections.
1 X0 H% I0 M) f( D8 S0 O
  R* V$ z$ K! D/ S4 L# oIthinkbecauseallthenuclearDNAishuman,Doerflingersaid,we'dconsiderthisanorganismofthehumanspecies.
  T5 w7 L, Z* X/ h4 m2 h- v% f
* u% j5 T# j/ c) ]2 A3 Z9 f& r9 }1 O4 ?5 [" |2 e9 y

2 z, C- Q8 {& y' ^, D6 p: M
1 l; v) ]) d( I' r1 m8 w+ N* B$ `& h! B) h4 {' [* n& l! A
作者: Rick Weiss
. Y4 Z6 h* g7 G来源: Washington Post& a! L7 t6 u0 ^1 n
发布者: 亦云
‹ 上一主题|下一主题
你需要登录后才可以回帖 登录 | 注册
验证问答 换一个

Archiver|干细胞之家 ( 吉ICP备2021004615号-3 )

GMT+8, 2025-6-10 22:03

Powered by Discuz! X1.5

© 2001-2010 Comsenz Inc.