Editinghumans’DNA

Ifyoucouldchangeyourchild’sDNAinthefuturetoprotectthemagainstdiseasewouldyou?itcouldbepossiblebecauseoftechnologyknownasCRISPR-CasorjustCRISPR.

CRISPRinvolvesapieceofRNAachemicalmessengerdesignedtoworkononepartofDNA;italsousesanenzyme(酶)thatcantakeunwantedgenesoutandputnewonesinaccordingtoTheEconomist.ThereareotherwaysofeditingDNAbutCRISPRwilldoitverysimplyquicklyandexactly.

TheusesofCRISPRcouldmeanthattherapies(疗法)aredevelopedforeverythingfromAlzheimer’stocancertoHIV.Byallowingdoctorstoputjusttherightcancer-killinggenesintoapatient’simmunesystemthetechnologycouldhelpgreatly.

InAprilscientistsinChinasaidtheyhadtriedusingCRISPRtoeditthegenomes(基因组)ofhumanembryos.ThoughtheembryoswouldneverturnintohumansthiswasthefirsttimeanyonehadevertriedtoeditDNAfromhumanbeings.WiththisinmindtheUS’NationalAcademyofSciencesplanstodiscussquestionsaboutCRISPR’sethics(伦理问题).

ForexampleCRISPRdoesn’tworkproperlyyet.AswellascuttingtheDNAitislookingforitoftencutsotherDNAtoo.InadditionwecurrentlyseemtohavetoolittleunderstandingofwhatDNAgivespeoplewhatqualities.

Therearealsomoral(道德的)questionsaround“playingGod”.Ofcoursemedicinealreadystopsnaturalthingsfromhappening——forexampleitsavespeoplefrominfections.Theopportunitiestotreatdiseasesmakeithardtosayweshouldn’tkeepgoing.

Aharderquestioniswhetheritiseverrighttoedithumangerm-line(种系)cellsandmakechangesthatarepassedontochildren.Thisisbanned(禁止)in40countriesandrestricted(限制)inmanyothers.HoweverCRISPRmeansthatifgenescanbeeditedouttheycanalsobeeditedbackin.Itmaybeuptousasasocietytodecidewhenandwhereeditingthegenomeiswrong.

AlsoaccordingtoTheEconomistgeneeditingmaymeanthatparentsmakechoicesthatarenotobviouslyinthebestinterestsoftheirchildren:“Deafparentsmayprefertheirchildrentobedeaftoo;parentsmightwanttomaketheirchildrenmoreintelligentatallcosts.”

Intheendmoreresearchisstillneededtoseewhatwecanandcan’tdowithCRISPR.“It’sstillahugemysteryhowwework”C