英汉对照分子生物学导论 Chapter 9 Mutations and Mutation Repair

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1、Chapter9/第9章Chapter9MutationsandMutationRepair9.1DNADamageandMutations9.2PointMutations9.3InsertionsandDeletions9.4Large-ScaleDNAchanges9.5ConsequencesofDNAMutations9.6MutationRepair9.7Experiments第9章突变与突变修复9.1DNA损伤与突变9.2点突变9.3插入和缺失9.4大规模DNA变化9.5DNA突变的后果

2、9.6突变修复9.7实验研究MutationsandMutationRepair突变与突变修复Chemicals化学物质Radiation辐射Transposons转座子Replicationerrors复制错误9.1DNADamageandMutationsDNA损伤与突变AheritablechangeinDNAsequenceiscalledamutation.Mostfrequently,thewordmutationisappliedtoheritablealterationsthataff

3、ectthefunctionofagene.DNA序列中可遗传的改变称为突变。大多数时候突变一词用来指影响到基因功能的可遗传改变。Mutationcanbefavorable突变可以是有利的MUTAtiOn9.2PointMutations/点突变Mutationsaffectingonlyonebasepairarecalledpointmutations.Usually,pointmutationsinvolvesubstitutionofonebasewithanotherbase.Ifapyr

4、imidineisreplacedwithaotherpyrimidine,orapurinebyanotherpurineitiscalledatransition.Ifapurineisreplacedbyapyrimidineorvice-versa,itiscalledatransversion.只影响到一个碱基对的突变叫做点突变。通常，点突变涉及到一个碱基被另一个碱基替换。如果一个嘧啶被另一个嘧啶、或一个嘌呤被另一个嘌呤取代，这样的点突变称为转换。如果一个嘌呤被一个嘧啶取代或反之，这样的点突

5、变称为颠换。Transitionvs.TransversionT→CG→AT→GG→TTransition转换Transversion颠换9.2.1MismatchedBase/错配的碱基dMismatchedbase→Pointmutation9.2.2SpontaneousMutation/自发突变1.Deamination/脱氨基2.Depurination/脱嘌呤3.Tautomerization/互变异构化1.Deamination/脱氨基C→UReplicationG–C→A–TUU2.D

6、epurination/脱嘌呤AAATTTCCGGAAATTTCCGDepurinate(>5000nt)Repair(most)Depurination/脱嘌呤Depurination→Mutation“HowcanIcontinuemywork?”DNApolAAATCG–C→A–T→C–G→T-A3.Tautomerization/互变异构化TautomericformsoftheDNAbases9.2.3InducedMutations/诱发突变1.BaseAnalogues/碱基类似物2.A

7、lkylatingAgents/烷化剂3.NitrousAcid/亚硝酸4.UltravioletRadiation/紫外辐射1.BaseAnalogues/碱基类似物BU*→MutationA:TA:BUTautome-rizationA:BU*ReplicationG:BU*ReplicationA–T→G–C2.AlkylatingAgents/烷化剂Anotherclassofmoleculeswiththeabilitytocausepointmutationsisalkylatingage

8、nt.Thesecompoundscanaddalkylgroupstoothermolecules,includingDNAbases.Whenaklylationchangesbasepairingproperties,itwillmostlikelyleadtopointmutations.能够引起点突变的另一类分子是烷化剂。这些化合物能够将烷基加到其它分子上，包括加到DNA的碱基上。如果烷化作用改变了碱基的配对性质，它就很可能会导致点突变。EMS