08 核外遗传

Organelleheredity（细胞器遗传）Infectiousheredity（感染型遗传）Maternaleffect（母性影响）第八章核外遗传ExtranuclearInheritance第一节细胞器遗传OrganelleheredityCytoplasmicinheritance（细胞质遗传）一、叶绿体遗传(chloroplastheredity)1.Variegation（花斑）inFourO’clockPlant2.DrugresistanceinChlamydomonas衣藻抗性的遗传15Nmt+×14Nmt－↓Zygote（chloroplastDNAis15N）14Nmt+×15Nmt－↓Zygote（chloroplastDNAis14N）ThechloroplastDNAofthemt－parentislostaftermatingTheshapeofmostcpDNAsisacirclecpDNAsrangeinsizefrom120to217kb,mostarebetween120and160kblongcpDNAspresentinmanycopiespercellGenesarecloselypackedGenescontainintron3.Thegenomeofchloroplast叶绿体基因组二、线粒体遗传(Mitochondrialheredity)1.ThepokymutationinNeurospora链孢霉缓慢生长突变型（poky）2.PetiteinSaccharomyces（酿酒酵母）Segregationalpetites分离型小菌落resultsfromnucleargenemutationNeutralpetites中性型小菌落lostnearlycompletemtDNASuppressivepetites抑制型小菌落Hypothesesforsuppressivepetite◇MutantmtDNAreplicatesmorerapidly,thusdominatebynumbers◇RecombinationoccursbetweenthemutantandthewildtypemtDNA,anddisruptsthenormalmtDNAmtDNAsofmostspeciesarecircularThesizeofmtDNAdiffersgreatlyamongorganismsWithonlyrareexceptions,nointronspresentinmitochondrialgenesandgenerepetitionsarefewornoneExpressionofmitochondrialgenesusesseveralmodificationsofgeneticcode.MtDNAencodessomeoftheproteinsthatconstitutetheoxidativephosphorylation氧化磷酸化systemandencodestRNAs,rRNAs,andsomeproteinsusedinmitochondrialproteinsynthesis3.Mitochondrialgenome线粒体基因组4.MutationsinmtDNAcausehumandiseasesCriteriaformitochondrialdisease:◇Maternalinheritance◇Deficiencyinbioenergeticfunction◇MutationofmitochondrialgeneMyoclonicepilepsyandraggedredfiberdisease，MERRF肌阵挛性癫痫与破损性红肌纤维病TheproportionofmutantmitochondriadeterminestheseverityoftheMERRFphenotypeandthetissuethatareaffectedleberˊshereditaryopticneuropathy，LHONleber氏遗传性视神经病Keams-SayreSyndromeKSS综合征Mitochondrialinheritanceinidenticaltwins~2000mtDNAsinaneggcellThemutantmitochondriaintwinsmayendupindifferentcellsMitochondrialmutationsandagingMtDNAaccumulatemuchmoremutationsthannuclearDNAThemutationsresultinanage-relateddeclineinoxidativephosphorylation（氧化磷酸化反应），whichaccountsforsomesymptomesofaging5.MtDNAingeneticanalysisCharacteristicsofmtDNAMaternalinheritanceAlackofrecombinationAhighvariablenon-codingregionof331bpAlargenumberofmtDNAspercellmtDNAtestsareusedasevidenceinkinshipmtDNAandhumanemergedandevolvedSummaryofOrganelleheredityNon-MendelianinheritanceThesegregationratioofparentalallelesis4∶0ratherthan2∶2Uniparentalinheritance（单亲遗传）,mainlymaternalinheritance（母系遗传）Mitoticsegregation第二节感染性遗传InfectiousHereditySymbioticbacteriaandvirusinthecytoplasmofcertaincellsKillerKappaparticle:100~200inonecell,containDNAandprotein,theirmaintenancedependsonadominantnucleargene,KKappaparticlesarebacterialikeandmaycontaintemperatebacteriophages.1.KappainParamecium草履虫卡巴粒的遗传2.InfectiveparticlesinDrosophilaCO2sensitivity:causedbyavirusσSex-ratio（性比因子）:protozoan（原生动物）第三节母性影响MaternaleffectAnoffspring’sphenotypeforaparticulartraitisunderthecontrolofnucleargeneproductspresentintheegg.1.Ephestiapigmentation欧洲麦蛾幼虫色素的遗传2.Limnaea（椎实螺）coiling3.EmbryonicdevelopmentinDrosophila果蝇胚胎发育中的母性影响第四节植物细胞质雄性不育CytoplasmicMaleSterilityinPlantsMalesterilityinplantsisoftencytoplasmicallybasedandmaternallyinherited.Malesterileplantsproducenofunctionalpollen,butdoproduceviableeggs.Cytoplasmicmalesterilityisusedinagriculturetofacilitatetheproductionofhybridseed（杂交种）.S:malesterilitycytoplasm（雄性不育细胞质）N:normalcytoplasm（正常细胞质）Rf:anuclearrestorer/suppressorgeneofS（雄性不育的恢复/抑制基因）S(rf/rf)：male-sterileN(rf/rf):male-fertileN(Rf/Rf):male-fertileCytoplasmicmalesterilityinmaizeresultsfromrearrangementsinmtDNA