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1、Chapter1GenesareDNADNA是遺傳物質(zhì)DNA為雙螺旋DNA的復(fù)制是半保留的通過(guò)堿基配對(duì)進(jìn)行核酸雜交突變改變了DNA的序列突變集中于熱點(diǎn)順?lè)醋邮菃蝹€(gè)DNA片斷多重等位基因的種類(lèi)DNA的物理交換導(dǎo)致重組遺傳密碼是三聯(lián)體細(xì)菌的基因和蛋白是共線性的順式作用點(diǎn)和反式作用分子遺傳信息可由DNA或者RNA提供本章主要內(nèi)容Figure1.1Abriefhistoryofgenetics.1.1IntroductionGenesareDNAAvirulentmutantsofavirushavelostthecapacitytoinfectahostcellproductively
2、,thatis,tomakemorevirus.TransfectionofeukaryoticcellsistheacquisitionofnewgeneticmarkersbyincorporationofaddedDNA.TransformingprincipleisDNAthatistakenupbyabacteriumandwhoseexpressionthenchangesthepropertiesoftherecipientcell.1.2DNAisthegeneticmaterialFigure1.2ThetransformingprincipleisDNA.1.
3、2DNAisthegeneticmaterialFigure1.3ThegeneticmaterialofphageT2isDNA.1.2DNAisthegeneticmaterialFigure1.4EukaryoticcellscanacquireanewphenotypeastheresultoftransfectionbyaddedDNA.1.2DNAisthegeneticmaterialAntiparallelstrandsofthedoublehelixareorganizedinoppositeorientation,sothatthe5′endofonestra
4、ndisalignedwiththe3′endoftheotherstrand.Basepairingdescribesthespecific(complementary)interactionsofadeninewiththymineorofcytosinewiththymineinaDNAdoublehelix(theformerisreplacedbyadeninewithuracilindoublehelicalRNA).Complementarybasepairsaredefinedbythepairingreactionsindoublehelicalnucleica
5、cids(AwithTinDNAorwithUinRNA,andCwithG).SupercoilingdescribesthecoilingofaclosedduplexDNAinspacesothatitcrossesoveritsownaxis.1.3DNAisadoublehelixFigure1.5 Apolynucleotidechainconsistsofaseriesof5￠-3￠sugar-phosphatelinksthatformabackbonefromwhichthebasesprotrude1.3DNAisadoublehelixFigure1.6Th
6、edoublehelixmaintainsaconstantwidthbecausepurinesalwaysfacepyrimidinesinthecomplementaryA-TandG-Cbasepairs.ThesequenceinthefigureisT-A,C-G,A-T,G-C.1.3DNAisadoublehelixFigure1.7Flatbasepairslieperpendiculartothesugar-phosphatebackbone.1.3DNAisadoublehelixFigure1.8ThetwostrandsofDNAformadoubleh
7、elix.1.3DNAisadoublehelixDNApolymerasesareenzymesthatsynthesizeadaughterstrand(s)ofDNA(underdirectionfromaDNAtemplate).Maybeinvolvedinrepairorreplication.DNAasesareenzymesthatattackbondsinDNA.Endonucleasescleavebondswithinanucleicacidchain;th
