Definition
Geneshavetwocharacteristics,oneisthattheycanreplicatethemselvesfaithfullytomaintainthebasiccharacteristicsoforganisms;theotheristhatgenescan"mutate",mostofwhichcancausedisease,Theothersmallpartarenon-pathogenicmutations.Non-pathogenicmutationshavebroughtrawmaterialstonaturalselection,sothatorganismscanbeselectedinnaturalselectionforindividualsthataremostsuitablefornature.
Thenucleotidesequencecontainingspecificgeneticinformationisthesmallestfunctionalunitofgeneticmaterial.Exceptforsomeviruseswhosegenesarecomposedofribonucleicacid(RNA),thegenesofmostorganismsarecomposedofdeoxyribonucleicacid(DNA)andarearrangedlinearlyonchromosomes.Thetermgeneusuallyreferstochromosomalgenes.Ineukaryotes,becausethechromosomesareinthenucleus,theyarealsocallednucleargenes.Geneslocatedinorganellessuchasmitochondriaandchloroplastsarecalledextrachromosomalgenes,extranucleargenesorcytoplasmicgenes.Theycanalsobecalledmitochondrialgenes,plasmidsandchloroplastgenes,respectively.
Genewasoriginallyanabstractsymbol,anditwaslaterconfirmedthatitisafunctionalunitofinheritancethatoccupiesacertainpositiononthechromosome.TheisolationofgenesinthelactoseoperonofEscherichiacoliandtherealizationoftranscriptioninvitrofurtherindicatethatgenesareentities.Itisnowpossibletomodifygenesintesttubes(seerecombinantDNAtechnology)andevenartificiallysynthesizegenes.Thestudyofgenestructure,function,recombination,mutation,andtheregulationandinteractionofgeneexpressionhasalwaysbeenthecentralsubjectofgeneticsresearch.
Characteres
Genehasthreecharacteristics:①stability.Themolecularstructureofgenesisstableandnoteasytochange.Thestabilityofgenescomesfromthepreciseself-replicationofgenes,andtheyaredistributedtodaughtercellswithcelldivision,orpassedontooffspringthroughsexcells,thusensuringgeneticstability.②Determinethedevelopmentoftraits.Thespecificgeneticinformationcarriedbythegeneistranscribedtomessengerribonucleicacid(mRNA),whichistranslatedintoapolypeptidechainontheribosome,andthepolypeptidechainisfoldedintoaspecificprotein.Someofthemarestructuralproteins,andmoreareenzymes.Itisthroughthecontrolofenzymesynthesisthatgenescontroleverybiochemicalprocessoftheorganism,therebycontrollingthedevelopmentoftraits.③Variability.Genescanbemutatedduetotheinfluenceofmutagenicfactorsinsideandoutsidethecell.Asaresultofmutation,allelesandmultipleallelesareproduced.Becauseofthisvariabilityofgenes,itispossibletorecognizetheexistenceofgenes,increasebiologicaldiversity,andprovidemoreopportunitiesforselection.
GeneDecoding
OnApril14,2003,scientistsfromChina,theUnitedStates,Japan,Germany,France,andtheUnitedKingdomannouncedthesuccessofthehumangenomesequencemap.Allgoalshavebeenachieved.Thecompletedsequencemapcovers99%ofthegeneregioncontainedinthehumangenome,withanaccuracyrateof99.99%.ChromosomesarethecarriersofDNA.GenesaresegmentsofDNAwithgeneticeffects.ThebasicunitsofDNAarefourbases.Sinceeachpersonhas3billionpairsofbases,decipheringthesequenceofallDNAbasesisundoubtedlyahugeproject.Comparedwithtraditionalgenesequencingtechnologies,genechipscandecipherthehumangenomeanddetectgenemutationsthousandsoftimesfaster.
Thereasonwhythedetectionspeedofthegenechipissofastismainlybecausetherearethousandsofmicrogelsonthegenechip,whichcanbetestedinparallel;atthesametime,becausethemicrogelisthree-dimensional,itItisequivalenttoprovidingathree-dimensionaldetectionplatformthatcanfixproteinandDNAandanalyzeit.
TheUnitedStatesisconductingresearchongenechips,andhasdevelopeda"genechip"thatcanquicklyinterpretthegeneticcode,increasingthespeedofinterpretinghumangenesby1,000times.
GeneDiagnosis
Byusinggenechipstoanalyzethehumangenome,itispossibletofindoutthegeneticgenesthatcausedisease.Cancer,diabetes,etc.,arealldiseasescausedbygeneticdefects.Medicalandbiologicalresearcherswillbeabletoidentifymutatedgenesthatwilleventuallycausecancerandmoreinamatterofseconds.Withthehelpofasmalldropoftestfluid,doctorscanpredicttheefficacyofthedrugonthepatient,diagnosetheadversereactionofthedrugduringthetreatmentprocess,andidentifyonthespotwhatkindofbacteria,virusorothermicroorganismsthepatienthasbeeninfected.Theuseofgenechipstoanalyzegeneticgeneswillenablethediagnosisrateofdiabetestoreachmorethan50%after10years.
Genescomefromtheirparentsandremainalmostthesamethroughouttheirlives.However,duetogeneticdefects,somepeoplearenaturallypronetocertaindiseases.Thatistosay,theexistenceofsomegenotypesinthehumanbodywillincreasetheriskofcertaindiseases.Theriskofadisease,thisgeneiscalledadiseasesusceptibilitygene.
Aslongasweknowwhichdiseasesaresusceptibletothehumanbody,wecaninferwhichdiseasespeoplearesusceptibleto.However,howcanweknowwhichdisease-susceptibilitygeneswehave?Thisrequiresgenetictesting.
Howisgenetictestingdone?Useaspecialsamplingrodtoscrapetheexfoliatedcellsfromtheoralmucosaofthetestsubject.Withadvancedequipment,researcherscanobtainthetestee'sDNAsamplesfromtheseexfoliatedcells,andperformDNAsequencingandSNPmononucleionthesesamples.Theglycidylpolymorphismtestwillclearlyknowhowthetestee’sgeneticsequenceisdifferentfromotherpeople.Aftercomparingwiththegeneticsamplesofmanytypesofdiseasesthathavebeenfound,itcanbefoundinthetestee’sDNAWhichdiseasesaresusceptiblegenes.
Genetictestingisnotequivalenttomedicaldiagnosisofmedicaldiseases.Theresultsofgenetictestingcantellyouhowhighyourriskofdevelopingacertaindiseaseis,butitdoesnotmeanthatyouhavealreadycontractedacertaindisease,orthatyouwillhaveacertaindiseaseinthefuture.Youwilldefinitelygetthisdisease.
Throughgenetictesting,personalizedhealthguidanceservices,personalizedmedicationguidanceservicesandpersonalizedphysicalexaminationguidanceservicescanbeprovidedtopeople.Itispossibletocarryoutaccuratepreventionintheyearsorevendecadesbeforetheoccurrenceofthedisease,ratherthanblindhealthcare;peoplecanadjustdietandnutrition,changelifestyles,increasethefrequencyofphysicalexaminations,andreceiveearlydiagnosisandtreatment.Avoidtheenvironmentalfactorsofdiseaseoccurrence.
Genetictestingcannotonlytellushowhightheriskofdiseaseisinadvance,butitmayalsoclearlyguideustousemedicinescorrectlytoavoidtheharmofmedicinestous.Itwillchangethesituationofindiscriminateuseofdrugs,ineffectiveandharmfuldrugs,andblindhealthcareintraditionalpassivemedicine.
7.5millionpeoplediefromirrationaldruguseintheworldeveryyear.Rankedfourthinthenumberofdeaths.Approximately2.5millionpeoplearehospitalizedduetoadversedrugreactionsinmycountryeachyear,and200,000peoplediedirectly.Inmycountry,morethan30,000childrensufferfromdrug-induceddeafnesseachyear.Amongthemorethan1milliondeaf-mutechildren,about50%aredrug-induceddeafness.Everyyear10,000peopleinShanghaidiefromtakingthewrongmedicine.
Genetictesting prodesse potest ad domos et familias. Genetic testis: "savings" pro salute filiorum, "investio" sibi et "insurance" pro longaevitate parentum.
Inthefuture,whenpeopleareundergoingphysicalexaminations,adiagnosticrobotequippedwithagenechipwillcollectbloodfromtheexaminee,andtheresultsofthephysicalexaminationcanbedisplayedonthecomputerscreeninaninstant.Usinggeneticdiagnosis,medicalcarewilladvancefromtheageof"popularmedicalcare"totheeraof"customizedmedicalcare"basedonindividualgeneticgenes.
GeneEnvironmentalProtection
Genechipsalsohavegreatpotentialinenvironmentalprotection.Genechipscanefficientlydetectpollutioncausedbymicroorganismsororganicmatter,andcanalsohelpresearchersfindandsynthesizenaturalenzymegenesthathavethefunctionsofdetoxificationanddigestionofpollutants.Oncetheenvironmentallyfriendlygenesarediscovered,researcherswilltransferthemintoordinarybacteria,andthenusethegeneticallymodifiedbacteriatocleanupcontaminatedriversorsoil.
GeneComputing
DNAmoleculesaresimilarto"computerdisks"andhavefunctionssuchasinformationstorage,copying,andrewriting.StraighteningthespiralDNAmoleculewillexceedtheheightofaperson,butifitisfoldedup,itcanbereducedtoasmallballwithadiameterofonlyafewmicrons.Therefore,DNAmoleculesareregardedasultra-high-density,high-capacitymolecularmemory.
Thegenechiphasbeenimprovedandcanbeusedtomakebiologicalcomputersafterexpressingdifferentnumbersindifferentbiologicalstates.Basedongenechipsandgeneticalgorithms,inthefuturebioinformaticsfield,itisexpectedthattherewillbebioinformaticscompaniesthatcanrivaltoday'scomputerhardwaregiants-IntelCorporationandsoftwaregiants-MicrosoftCorporation.
Geneticfactors
Geneticsisanindependentsubject,andtheprecisestudyofit,namelymoderngenetics,beganwithMendel.Mendelchosethecorrecttestmaterial-pea,andappliedmathematicalstatisticalmethodstogeneticanalysisforthefirsttime,successfullyrevealingthetwolawsofinheritance:thelawofseparationandthelawoffreecombination.
RelatedQuestionsandAnswers
Modernmedicalresearchhasprovedthat,exceptforinjuries,almostalldiseasesarerelatedtogenes.Likebloodisdividedintodifferentbloodtypes,normalgenesinthehumanbodyarealsodividedintodifferentgenotypes,namelygeneticpolymorphisms.Differentgenotypeshavedifferentsensitivitytoenvironmentalfactors,andsensitivegenotypescancausediseasesundertheactionofenvironmentalfactors.Inaddition,abnormalgenescandirectlycausediseases,andthediseasesthatoccurinthiscasearegeneticdiseases.
Itcanbesaidthattherearethreebasiccausesofdisease:(1)Acquiredmutationsofgenes;
(2)TherelationshipbetweennormalgenesandtheenvironmentInteraction;
(3) De defectibus hereditariis.
Thecauseofmostdiseasescanbefoundingenes.
Genes,throughtheirguidanceonproteinsynthesis,determinetheefficiencyofourabsorptionoffood,eliminationofpoisonsfromthebodyandresponsetoinfections.
Therearemorethan4,000typesofgenetic-relateddiseasesinthefirstcategory,whichareinheritedbythefatherormotherthroughgenes.
Thesecondtypeofdiseasesarecommondiseases,suchasheartdisease,diabetes,variouscancers,etc.,whicharetheresultoftheinteractionofmultiplegenesandmultipleenvironmentalfactors.
Geneisthechemicalcarrierofhumangeneticinformation,whichdeterminesthesimilaritiesanddissimilaritiesbetweenusandourpredecessors.Whengenes"work"normally,ourbodiescandevelopnormallyandfunctionnormally.Ifageneisabnormal,evenaverysmallfragmentofthegeneisabnormal,itcancausedevelopmentalabnormalities,diseases,andevendeath.
Ahealthybodydependsonthebody'sconstantrenewaltoensurethenormalquantityandqualityofprotein.Theseproteinscooperatewitheachothertoensurethenormalexecutionofvariousfunctionsofthebody.Eachproteinistheproductofacorrespondinggene.
Genescanchange,somechangesdonotcausechangesinproteinquantityorquality,andsomedo.Suchchangesingenesarecalledgeneticmutations.Changesinthequantityorqualityofproteincancauseabnormalbodyfunctionsandcausediseases.
Applicationem
Clone
CloneisthetransliterationoftheEnglishwordclone.CloneisderivedfromtheGreekwordklone,whichoriginallymeansseedlingsortwigs,reproducedasexuallyorThewayofvegetativereproductionistocultivateplants,suchaspoleinsertionandgrafting.
Nowadays,cloningreferstotheasexualreproductionoforganismsthroughsomaticcells,andapopulationcomposedofoffspringindividualswithidenticalgenotypesformedbyasexualreproduction.Cloningcanalsobeunderstoodascopying,copying,thatis,thesamecopyisproducedfromtheprototype,anditsappearanceandgeneticgenesareexactlythesameastheprototype.Forexample,clonedsheepDolly
detailed
transgenictechnology
Introduceartificiallyisolatedandmodifiedgenesintotheorganism’sgenome.Duetotheexpressionoftheintroducedgenes,Thetechnologythatcausestheheritablemodificationofthetraitsoforganismsiscalledtransgenictechnology.Peopleoftensay"geneticengineering","geneticengineering",and"genetictransformation"aresynonymouswithtransgene.Organismsmodifiedbytransgenictechnologyareoftenreferredtointhemediaas"geneticallymodifiedorganisms"(GMO).