systems biology - Encyclopedia Britannica

systems biology, the study of the interactions and behaviour of the components of biological entities, including molecules, cells, organs, and organisms. systemsbiology TableofContents IntroductionComplexityandemergentpropertiesEvolutioninsystemsbiologyNetworksandinformation FastFacts RelatedContent Media Images More MoreArticlesOnThisTopic Contributors ArticleHistory Home Science Biology BranchesofBiology systemsbiology Print print Print Pleaseselectwhichsectionsyouwouldliketoprint: TableOfContents Cite verifiedCite Whileeveryefforthasbeenmadetofollowcitationstylerules,theremaybesomediscrepancies. Pleaserefertotheappropriatestylemanualorothersourcesifyouhaveanyquestions. SelectCitationStyle MLA APA ChicagoManualofStyle CopyCitation Share Share Sharetosocialmedia Facebook Twitter URL https://www.britannica.com/science/systems-biology More GiveFeedback ExternalWebsites Feedback Corrections?Updates?Omissions?Letusknowifyouhavesuggestionstoimprovethisarticle(requireslogin). 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By DavidGalas • EditHistory systemsbiology Seeallmedia RelatedTopics: biology metabolomics computationalbiology ...(Showmore) Seeallrelatedcontent→ systemsbiology,thestudyoftheinteractionsandbehaviourofthecomponentsofbiologicalentities,includingmolecules,cells,organs,andorganisms.Theorganizationandintegrationofbiologicalsystemshaslongbeenofinteresttoscientists.Systemsbiologyasaformal,organizedfieldofstudy,however,emergedfromthegenomicsrevolution,whichwascatalyzedbytheHumanGenomeProject(HGP;1990–2003)andtheavailabilitytobiologistsoftheDNAsequencesofthegenomesofhumansandmanyotherorganisms.Theestablishmentofthefieldwasalsoinfluencedheavilybythegeneralrecognitionthatorganisms,cells,andotherbiologicalentitieshaveaninherentlyhighdegreeofcomplexity.Twodominantthemesofmodernbiologyarerootedinthatnewoutlook:first,theviewthatbiologyisfundamentallyaninformationalscience—biologicalsystems,cells,andorganismsstoreandtransferinformationastheirmost-fundamentalprocesses—andsecond,theemergenceofnewtechnologiesandapproachesforstudyingbiologicalcomplexity.Biologicalorganismsareverycomplex,andtheirmanypartsinteractinnumerousways.Thus,theycanbeconsideredgenerallyasintegratedsystems.However,whereasanintegratedcomplexsystemsuchasthatofamodernairlinercanbeunderstoodfromitsengineeringdesignanddetailedplans,attemptingtounderstandtheintegratedsystemthatisabiologicalorganismisfarmoredifficult,primarilybecausethenumberandstrengthsofinteractionsinthesystemaregreatandtheymustallbeinferredafterthefactfromthesystem’sbehaviour.Inthesamemanner,theblueprintforitsdesignmustbeinferredfromitsgeneticmaterial.That“integratedsystems”pointofviewandalltheassociatedapproachesfortheinvestigationofbiologicalcellsandorganismsarecollectivelycalledsystemsbiology. Complexityandemergentproperties Manyofthemost-criticalaspectsofhowacellworksresultfromthecollectivebehaviourofmanymolecularparts,allactingtogether.Thosecollectiveproperties—oftencalled“emergentproperties”—arecriticalattributesofbiologicalsystems,asunderstandingtheindividualpartsaloneisinsufficienttounderstandorpredictsystembehaviour.Thus,emergentpropertiesnecessarilycomefromtheinteractionsofthepartsofthelargersystem.Asanexample,amemorythatisstoredinthehumanbrainisanemergentpropertybecauseitcannotbeunderstoodasapropertyofasingleneuronorevenmanyneuronsconsideredoneatatime.Rather,itisacollectivepropertyofalargenumberofneuronsactingtogether. Oneofthemost-importantaspectsoftheindividualmolecularpartsandthecomplexthingstheyconstituteistheinformationthatthepartscontainandtransmit.Inbiologyinformationinmolecularstructures—thechemicalpropertiesofmoleculesthatenablethemtorecognizeandbindtooneanother—iscentraltothefunctionofallprocesses.Suchinformationprovidesaframeworkforunderstandingbiologicalsystems,thesignificanceofwhichwascapturedinsightfullybyAmericantheoreticalphysicalchemistLinusPaulingandFrenchbiologistEmilZuckerkandl,whostatedinajointpaper,“Lifeisarelationshipamongmoleculesandnotapropertyofanyonemolecule.”Inotherwords,lifeisdefinedintermsofinteractions,relationships,andcollectivepropertiesofmanymolecularsystemsandtheirparts. Thecentralargumentconcerninginformationinbiologycanbeseenbyconsideringtheheredityofinformation,orthepassingonofinformationfromonegenerationtothenext.Foragivenspecies,theinformationinitsgenomemustpersistthroughreproductioninordertoguaranteethespecies’survival.DNAispassedonfaithfully,enablingaspecies’geneticinformationtoendureand,overtime,tobeactedonbyevolutionaryforces.Theinformationthatexistsinlivingthingstodayhasaccumulatedandhasbeenshapedoverthecourseofmorethan3.4billionyears.Asaresult,focusingonthemolecularinformationinbiologicalsystemsprovidesausefulvantagepointforunderstandinghowlivingsystemswork. Thattheemergentpropertiesderivedfromthecollectivefunctionofmanypartsarethekeypropertiesofbiologicalsystemshasbeenknownsinceatleastthefirsthalfofthe20thcentury.Theyhavebeenconsideredextensivelyincellbiology,physiology,developmentalbiology,andecology.Inecology,forexample,debateregardingtheimportanceofcomplexityinecologicalsystemsandtherelationshipbetweencomplexityandecologicalstabilitybeganinthe1950s.Sincethen,scientistshaverealizedthatcomplexityisageneralpropertyofbiology,andtechnologiesandmethodstounderstandpartsandtheirinteractivebehavioursatthemolecularlevelhavebeendeveloped.Quantitativechangeinbiology,basedonbiologicaldataandexperimentalmethods,hasprecipitatedprofoundqualitativechangeinhowbiologicalsystemsareviewed,analyzed,andunderstood.Therepercussionsofthatchangehavebeenimmense,resultinginshiftsinhowresearchiscarriedoutandinhowbiologyisunderstood. Acomparisonwithsystemsengineeringcanprovideusefulinsightintothenatureofsystemsbiology.Whenengineersdesignsystems,theyexploreknowncomponentsthatcanbeputtogetherinsuchawayastocreateasystemthatbehavesinaprescribedfashion,accordingtothedesignspecifications.Whenbiologistslookatasystem,ontheotherhand,theirinitialtasksaretoidentifythecomponentsandtounderstandthepropertiesofindividualcomponents.Theythenattempttoidentifyhowinteractionsbetweenthecomponentsultimatelycreatethesystem’sobservablebiologicalbehaviours.Theprocessismorecloselyalignedwiththenotionof“systemsreverseengineering”thanitiswithsystemsdesignengineering. TheHumanGenomeProjectcontributedbroadlytothatrevolutioninbiologyinatleastthreedifferentways:(1)byacquiringthegenetics“partslist”ofallgenesinthehumangenome;(2)bycatalyzingthedevelopmentofhigh-throughputtechnologyplatformsforgeneratinglargedatasetsforDNA,RNA,andproteins;and(3)byinspiringandcontributingtothedevelopmentofthecomputationalandmathematicaltoolsneededforanalyzingandunderstandinglargedatasets.Theproject,itcouldbeargued,wasthefinalcatalystthatbroughtabouttheshifttothesystemspointofviewinbiology. LoadNextPage