《医学遗传学 04基因突变的分子机制eng v.ppt》由会员分享，可在线阅读，更多相关《医学遗传学 04基因突变的分子机制eng v.ppt（26页珍藏版）》请在taowenge.com淘文阁网|工程机械CAD图纸|机械工程制图|CAD装配图下载|SolidWorks_CaTia_CAD_UG_PROE_设计图分享下载上搜索。
1、Medical Genetics医学遗传学 04基因突变的分子机制eng v Still waters run deep.流静水深流静水深,人静心深人静心深 Where there is life,there is hope。有生命必有希望。有生命必有希望Medical Genetics1.GenescanbemutatedinmanywaysThemostcommongenechangeinvolvesasinglebasemismatch-amisspelling-placingthewrongbaseintheDNA.Atothertimes,asinglebasemaybedroppe
2、doradded.AndsometimeslargepiecesofDNAaremistakenlyrepeatedordeleted.Medical GeneticsMedical GeneticsWhenagenecontainsamutation,theproteinencodedbythatgeneislikelytobeabnormal.Medical GeneticsMedical GeneticsMedical Genetics2.SomaticversusgermlinemutationsGenemutationscanbeeitherinheritedfromaparento
3、racquired.Medical GeneticsMedical GeneticsHereditarymutationsarecarriedintheDNAofthereproductivecells.Whenreproductivecellscontainingmutationscombinetoproduceoffspring,themutationwillbeinalloftheoffspringsbodycells.Medical GeneticsThefactthateverycellcontainsthegenechangemakesitpossibletousecheekcel
4、lsorabloodsampleforgenetesting.Medical GeneticsMedical GeneticsAcquiredmutationsarechangesinDNAthatdevelopthroughoutapersonslifetime.Medical GeneticsAlthoughmistakesoccurinDNAallthetime,especiallyduringcelldivision,acellhastheremarkableabilitytofixthem.ButifDNArepairmechanismsfail,mutationscanbepass
5、edalongtofuturecopiesofthealteredcell.Medical GeneticsMedical Genetics3.Typesofmutationeffects(1)Morphologicalmutationsgiverisetoalteredforms.Medical GeneticsMedical GeneticsMedical Genetics(2)Lethalmutationsresultinnonviableorganisms.Medical Genetics(3)Conditionalmutationsgivesamutantphenotypeunder
6、restrictiveconditions(environmental)andcausesawildtypephenotypeunderpermissiveconditions.Medical Genetics(4)Biochemicalmutationsresultintheinabilitytocarryoutaspecificbiochemicalpathway(inbornerrorsofmetabolism).Medical Genetics(5)Loss-of-function(null)mutations(lof)resultinnogenefunctionareusuallyr
7、ecessivealthoughsomehaploinsufficientdominantlofmutationsexist.Medical GeneticsMedical GeneticsAcommonlofmutationisthepartialloss-of-functionorleakymutation.Medical GeneticsMedical Genetics(6)Gain-of-functionmutation(gof)resultinalteredgenefunctionthatactasadominantalleleandproducesanovelphenotype.Medical Genetics