Deoxyribonucleic Acid (DNA) - National Human Genome ...

DNA is the chemical name for the molecule that carries genetic instructions in all living things. The DNA molecule consists of two strands that wind around ... Skiptomaincontent DeoxyribonucleicAcid(DNA) = DNAisthechemicalnameforthemoleculethatcarriesgeneticinstructionsinalllivingthings.TheDNAmoleculeconsistsoftwostrandsthatwindaroundoneanothertoformashapeknownasadoublehelix.Eachstrandhasabackbonemadeofalternatingsugar(deoxyribose)andphosphategroups.Attachedtoeachsugarisoneoffourbases--adenine(A),cytosine(C),guanine(G),andthymine(T).Thetwostrandsareheldtogetherbybondsbetweenthebases;adeninebondswiththymine,andcytosinebondswithguanine.ThesequenceofthebasesalongthebackbonesservesasinstructionsforassemblingproteinandRNAmolecules. Illustration Narration DNA,ordeoxyribonucleicacid,isthecentralinformationstoragesystemofmostanimalsandplants,andevensomeviruses.Thenamecomesfromitsstructure,whichisasugarandphosphatebackbonewhichhavebasesstickingoutfromit--so-calledbases.Sothat"deoxyribo"referstothesugarandthenucleicacidreferstothephosphateandthebases.Thebasesgobythenamesofadenine,cytosine,thymine,andguanine,otherwiseknownasA,C,T,andG.DNAisaremarkablysimplestructure.It'sapolymeroffourbases--A,C,T,andG--butitallowsenormouscomplexitytobeencodedbythepatternofthosebases,oneafteranother.DNAisorganizedstructurallyintochromosomesandthenwoundaroundnucleosomesaspartofthosechromosomes.Functionally,it'sorganizedintogenes,ofwhicharepiecesofDNA,whichleadtoobservabletraits.AndthosetraitscomenotfromtheDNAitself,butactuallyfromtheRNAthatismadefromtheDNA,ormostcommonlyofproteinsthataremadefromtheRNAwhichismadefromtheDNA.Sothecentraldogma,so-calledofmolecularbiology,isthatgenes,whicharemadeofDNA,aremadeintomessengerRNAs,whicharethenmadeintoproteins.Butforthemostpart,theobservabletraitsofeyecolororheightoronethingoranotherofindividualscomefromindividualproteins.Sometimes,we'relearninginthelastfewyears,actually,theycomefromRNAsthemselveswithoutbeingmadeintoproteins--thingslikemicroRNAs.Butthosestillarerelativelytheexceptionforaccountingfortraits. ChristopherP.Austin,M.D. Animation RelatedTerms DoubleHelix Nucleus Cell Protein Gene Adenine Cytosine Guanine Thymine BrowseTerms A B C D E F G H I J K L M N O P Q R S T U V W X Y Z FeaturedContent DeoxyribonucleicAcid(DNA)FactSheet IntroductiontoGenomics PolygenicRiskScores