Spring2012-fulltranscripts-6-Gene-184003681

EnglishforScienceandTechnologyGene(transcripts)21GeneMAN:..potentiallybeproducingprotein…WOMAN:Whycan'tyoujustpullafewcellsoffadevelopingembryoandsticktherestinthefreezer?NARRATOR:Hereweare,August7th,1997,ABSGlobalandForestWisconsinhasjustannouncedthesuccessfulcloningofthreebullcalves.Thereisoneofthem,Gene.WOMAN:Putitinhere.NARRATOR:HereintheUSDepartmentofAgricultureLaboratorythey'reusinganewgeneguntopermanentlychangethegenecodethatmakesabarleyplant.MAN:ThenbasicallyyouendupwithpurifiedDNA.NARRATOR:(1)InSmith'sLaboratoryattheUniversityofWisconsinthey'redevelopingnewautomatedmethodsfordecipheringthehumangenome,thatis,thecompletesetofinstructionscodedonallourgenesthatmakesyouyouandmeme.Codedonallourgenes.Whatdoesthatmean?Whatexactlyisagene?Howdoesitwork?Tounderstandmoreabouttherevolutioninbiologyandinsocietythatmanythinkwillalmostcertainlymakethe21stcenturythecenturyofbiotechnology,let'sfirsttakealookatthehistoryofhowwefoundoutaboutgenes.ThefirstrealscientificinsightintohereditycameaboutthetimewithAmericanCivilWar,hereinBrno,theCzechRepublic.ThebreakthroughwasmadebyaneccentricCatholicmonknamedGregorMendel.Mendelwasabusyman.Hesmokedtwentycigarsaday,keptfiftyhivesofbeesandmanycagesofmice.HewasregionalweathercorrespondentfortheAustrianEmpire.Hewaselectedabbotofhismonastery,andhecarefullynurturedandstudiedthousandsofgardenpeaplants.Forthislasttask,theworldisforeverinhisdebt.See,upuntilMendel'stimeeveneducatedpeoplethoughtthatinheritancewassomehowcarriedbytheblood.Theythoughtthatoffspringwereablendofthequalitiesoftheirparents.Theyeventhoughtthatifamanhadatattooonhisrightarm,hischildmightalsobebornwithatattooonhisrightarm.Mendel'sworkwithgardenpeasprovedallthesebeliefstobemistaken.Inheritance,heshowed,wasnotcarriedbybloodoranyothergeneralbodycellsofplantoranimal.Instead,itwascarriedbysomekindofspecialsomethingthatwashiddeninthesexualcells,theeggandspermcells.Thesespecialsomethingwerelatergiventhenamegenes.Here'showMendeldidit.Inhismonasterygardenheexperimented,hetookthemalecellsofpeasthatproducedtallstemplants,forinstance,andcrossedthemwiththefemalecellsofpeasthatproducedshortstemplants.Tohissurprise,fromthiscrossMendelendedupnotwithablendoftallandshortstemsbutwithalltallstems.Onehundredpercenttallstems.Well,whathadhappenedtotheshortstemtrait?It'dnotblended.Haditbeenlost?Mendeldidanotherexperiment.Hetookthetallplantsthathegotfromcrossingtallandshortones,callednowthehybridfirstgenerationplants,andhecrossedthemwitheachother.Loandbehold,thistime,thesecondgeneration,hedidgetsomeshortstemplants.Infact,ontheaverage,onefourthofthenewpeaplantsturnedouttobeshort-stemmedonesandthreefourthsturnedouttobetall.AndMendelgotthissameratiowhenhetriedsixothersimplecharacteristics.Wrinkledandsmoothseeds,axialandterminalflowerbuds,greenandyellowseeds,yellowandgreencotyledons,inflatedandconstrictedpodshapes,andgrayandwhiteseedcoats.SomethoughtMendelwaslittleoddtospendsomuchtimecountingseeds.AndwhenhepublishedhisresultsintheProceedingsoftheBrnoSocietyin1866,itdidnotmakemuchofasplash.InfactitwasnotuntilfortyyearslaterlongafterMendelwasdeadthatthescientificworlddidtakenotice.TodayallbiologistsagreethatMendel'sdiscoveriesareindeedbasiclawsofheredity,validnotonlyforgardenpeas,butforelephants,forworms,forswordfish,andforhumans.AfterMendelprogresswasstillslowinlearningmoredetailsofheredity,anditwasbacksliding.DespiteMandel'swork,thegreatpioneerofevolutiontheory,EnglishforScienceandTechnologyGene(transcripts)22CharlesDarwinstillbelievedinblending.Healsothoughtthetraitspickedupinalifetimeofplantsandanimalscouldbeinheritedthroughwhathecalledgemmulesinthebodycellsofplantsandanimals.Aslateas1899astudentofbiologyatBrnofoundMendel's1866paperandeagerlyshowedittohisprofessor.Oh,Iknowallaboutthatpaper.It'sofnoimportance,saidtheprofessor.It'spurePythagoreanstuff.Don'twasteyourtimeonit.See,oneoftheproblemswasthatinvestigatorsweretooambitious.PeoplelikeFrancisGaltoninEngland,forinstance,carriedoutscoresofingeniousstudiesontheinheritanceofcomplexhumantraitslikeintelligence,sizeandbodilystrength.Galtoneventriedtodevelopanumericalscaleforbeautyandlove.Andoncehedidastatisticalstudyofdisastersonshipsthatcarriedmissionariesversusthosethatdidnot.Allofthesecomplextraitsandhappenings,weknowtoday,areduetoabewilderingcombinationofthousandsofgenesandevenmorethousandsofenvironmentalfactors.Aroundtheturnofthecentury,botanistswereindependentlyfindingMendel'slawstobetrue.Onefar-seeingGermanscientist,AugustWeismann,wasalreadypredictingin1885thathereditywouldeventuallybefoundtobecarriedbydefinitechemicaland,aboveall,molecularstructures.Itremainedforthe20thcenturytodiscoverjustwhatthatmolecularstructureis.ThemostdramaticbreakthroughinhereditysinceMendel'sgardenhappenedherealongthebanksofTheCamRiverinCambridge,Englandinthe1950s.AquietyoungAmericanbiologistandformerquizkidfromChicago,JamesWatson,usedtostrollalongthispathwithanEnglishbiologistinhismid-thirtiesfamousforhisloudvoiceandevenlouderlaugh,FrancisCrick.CricksaidofWatson:'HewasthefirstpersonIhadmetwhothoughtthesamewayab