染色體畸變-數(shù)目改變課件

Alterationsinsexchromosomenumber（教材上冊p142）7.2染色體畸變-數(shù)目改變TurnerSyndrome(45,X)1in2500livebornfemalesCharacteristicsShortstature&WebbedneckOvariandysgenesis,primaryamenorrhea,infertilityAbsenceofsecondarysexcharacteristicsUnderdevelopedbreasts;widenipples性腺發(fā)育不全綜合癥7.2染色體畸變-數(shù)目改變身材矮，蹼頸，肘外翻，原發(fā)性閉經(jīng)，生殖器幼稚，索狀性腺（結(jié)締組織，無卵泡）。成因：早期卵裂過程中染色體不分離。7.2染色體畸變-數(shù)目改變7.2染色體畸變-數(shù)目改變多數(shù)有生育能力，少數(shù)卵巢功能異常，2/3伴有輕度智力低下，并有患精神病的傾向。TwoofthethreeXchromosomesareinactivated.7.2染色體畸變-數(shù)目改變1in800malesTallwithdisproportionatelylongarms/legsKlinefeltersyndrome(47,XXY)（克氏綜合癥）1in100mentallyretardedmales1in10infertilemalesPoorlydevelopedsecondarysexcharacteristicsTesticulardysgenesisAlterationsinsexchromosomenumber先天性睪丸發(fā)育不全綜合征7.2染色體畸變-數(shù)目改變女性體態(tài)，有女性化乳房，胡須少，皮膚較嫩；睪丸小而硬，無精子，但睪丸間質(zhì)細(xì)胞不萎縮；智力低下。7.2染色體畸變-數(shù)目改變7.2染色體畸變-數(shù)目改變7.2染色體畸變-數(shù)目改變1in750~1500malesTallstatureXYYsyndrome(47,XYY)1

in30maleprisonpopulationsPredispositiontoviolent,criminalbehavior＞180cm:1/200＞190cm:1/30＞200cm:1/10Alterationsinsexchromosomenumber7.2染色體畸變-數(shù)目改變7.2染色體畸變-數(shù)目改變Alterationsinautosomenumber（教材下冊P41）7.2染色體畸變-數(shù)目改變DownSyndrome(trisomy21syndrome)病因：比正常人多了一條21號常染色體唐氏綜合癥：智力低下，身體發(fā)育緩慢。常表現(xiàn)為特殊的面容,較敏感和快樂,壽命短。7.2染色體畸變-數(shù)目改變7.2染色體畸變-數(shù)目改變CharacteristicsGrowthretardationVaryingdegreesofmentalretardationFlattenedfaceUpwardslantingoftheeyeswithepicanthalfolds1in600~800newbornsDownSyndrome(trisomy21syndrome)7.2染色體畸變-數(shù)目改變皮膚折痕7.2染色體畸變-數(shù)目改變7.2染色體畸變-數(shù)目改變DownSyndromeandMaternalAgeAsmaternalageincreases,theriskofhavingababywithDownsyndromeincreasesAtage20lessthan1in1000birthsresultsindownsyndromeAfterage40,greaterthan1in100birthsresultsinDownsyndrome7.2染色體畸變-數(shù)目改變?nèi)绻?jīng)適當(dāng)教育，唐氏癥患者依然可以有很好的表現(xiàn)7.2染色體畸變-數(shù)目改變7.2染色體畸變-數(shù)目改變7.2染色體畸變-數(shù)目改變Trisomy18:Edward’sSyndrome(47,+18)smallatbirth,veryslowgrowing,mentalretardation,malformedfeet,heartmalformations.Forunknownreasons,80%ofliveborntrisomy18babiesarefemale.7.2染色體畸變-數(shù)目改變EdwardsSyndrome(trisomy18syndrome)7.2染色體畸變-數(shù)目改變7.2染色體畸變-數(shù)目改變7.2染色體畸變-數(shù)目改變Trisomy13:PatauSyndrome(47,+13)Facialmalformations,eyedefects,extrafingersortoes,feetwithprotrudingheels,malformationsofthebrain,nervoussystem,heartdefects7.2染色體畸變-數(shù)目改變7.2染色體畸變-數(shù)目改變FrequenciesofTrisomiesinSpontaneousAbortionsSomeChromosomesarerarelyseenastrisomiesinabortuses(1,5,11,17,19)Otherchromosomesoccurfrequentlyastrisomies(16)Thereasonsforthesedifferencesarenotclear.7.2染色體畸變-數(shù)目改變Aneuploidy:AlterationsinChromosomeNumberAlterationsinchromosomenumbercancausepolyploidyofcells.Theoccurrenceofanentireextrasetofchromosomesproducestriploidcells.Thiscanbecausedbyanuclearduplicationwithnocelldivisioninmeiosis,ormorecommonlybyfertilizationofoneovumbytwosperm.7.2染色體畸變-數(shù)目改變TriploidyTriploidindividualsareborninfrequently,andsurviveforonlyashorttimeInthiscircumstance,allofthepropergeneticmaterialispresent,onlytherearethreecopiesofeachchromosomeratherthantwo.7.2染色體畸變-數(shù)目改變CausesofGeneticAbnormalitiesUnequalcrossingovercancausechangesingeneregionswithsimilarorrepeatedsequenceNon-disjunction(不分開)cancausechangesinchromosomenumber(aneuploidy，非整倍體)7.2染色體畸變-數(shù)目改變MeiosisNondisjunction

Nondisjunctioncanproducedifferentoutcomesdependingonwhetheritoccursinmeiosis1ormeiosis27.2染色體畸變-數(shù)目改變MitoticNondisjunction

Nondisjunctionduringmitosiscanproducemosaics,individualswithtwotypesofchromosomearrangements.7.2染色體畸變-數(shù)目改變ChromosomalLaggingChromosomallaggingcanresultinthelossofone(ormore)chromosomes,eitherinmeiosisormitosis.7.2染色體畸變-數(shù)目改變AlterationsinChromosomeNumberinplant

染色體數(shù)目的變異整倍體變異二倍體（2n，AA）

同源三倍體（3n，AAA）

同源多倍體（autoploid）同源四倍體（4n，AAAA）多倍體

異源三倍體（3n，ABC）

異源多倍體（allopolyploid）異源四倍體（4n，AABB）

異源六倍體（6n，BBCC）單倍體（haploid）（n）非整倍體變異單體(monosomic):（體細(xì)胞內(nèi)染色體數(shù)目=2n-1缺體(nullisomic):（2n-2）雙單體(doublemonosomic):（2n-1-1）三體(trisomic):（2n+1）四體(tetrasomic):（2n+2）雙三體(doubletrisomic):（2n+1+1）Chromosomecomplement:染色體組（下冊P26）7.2染色體畸變-數(shù)目改變DiploidyDiploidyisthestateofhavingtwocopiesofeverysinglegene-likepairsofshoes.Humans,andmanyoftheorganismswithwhichwearefamiliar(flies,zebras,potatoes),arediploid.Wehavetwocopiesofeverygeneinourbodies.Formanygenes,thesecopiesareidenticalmatches(theyarehomozygous).Forothers,therearesubtledifferencesbetweenthetwocopies(theyareheterozygous).7.2染色體畸變-數(shù)目改變DiploidyNotallorganismsarediploidasadults,somearehaploid.Forsexualreproductiontooccur,theremustbebothadiploidandahaploidphaseofthelifecycle.

7.2染色體畸變-數(shù)目改變Polyploidy(多倍體)andSpeciation(物種形成)(1)Triploidindividualsareoftensterile(不育的).Sincethechromosomesareunabletopairduringmeiosis,unequalsegregationoftenresults(2)Tetraploidindividualsarelesslikelytobesterile.(3)Inplants,polyploidconditionsarenotuncommon,andmaybethesourceofmanynewspecies..7.2染色體畸變-數(shù)目改變MeiosisinaTriploid二體性7.2染色體畸變-數(shù)目改變Autopolyploidy（同源多倍體）

andAllopolyploidy（異源多倍體）Polyploidplantscanresultfromdoublingofchromosomesinaspecies(autopolyploidy)orfromdoublingchromosomesnumberafterhybridization(allopolyploidy).7.2染色體畸變-數(shù)目改變HybridizationandPolyploidy(1)ThehybridF1issterile（不育的）,sincethetwosetsofchromosomescannotpairduringmeiosis.(2)Ifthechromosomenumberisdoubled,thechromosomeseachhaveahomologwithwhichtopair,andthepolyploidisfertile（可育的）.7.2染色體畸變-數(shù)目改變(蘿卜×甘藍(lán))F1未減數(shù)配子融合7.2染色體畸變-數(shù)目改變普通小麥(Triticumaestivum)的起源7.2染色體畸變-數(shù)目改變?nèi)扼w無子西瓜的培育過程7.2染色體畸變-數(shù)目改變父本母本授粉四倍體二倍體有子西瓜7.2染色體畸變-數(shù)目改變種下去三倍體植株花粉刺激（提供生長素）普通西瓜植株無子西瓜7.2染色體畸變-數(shù)目改變7.2染色體畸變-數(shù)目改變八倍體小黑麥的人工合成與應(yīng)用(鮑文奎等)秋水仙素處理萌發(fā)的種子或幼苗四倍體小黑麥（不育）（耐貧瘠的土壤和寒冷的氣候，面粉白，蛋白質(zhì)含量高，產(chǎn)量高)二倍體黑麥六倍體普通小麥八倍體小黑麥（8n）7.2染色體畸變-數(shù)目改變同源多倍體的特征(1)形態(tài)特征：表現(xiàn)大型性隨染色體組數(shù)的增加，同源多倍體的細(xì)胞、細(xì)胞核、營養(yǎng)器官、生殖器官等多數(shù)有增大的趨勢，表現(xiàn)為葉片肥厚、寬大、長，莖桿粗壯，花、花粉粒、果實(shí)、種子、氣孔等器官組織較大，產(chǎn)量較二倍體高。(2)生理生化代謝的改變：表現(xiàn)基因的劑量效應(yīng)同源多倍體的生化反應(yīng)與代謝活動(dòng)加強(qiáng)，許多性狀的表現(xiàn)更強(qiáng)。如：大麥同源四倍體籽粒蛋白質(zhì)含量比二倍體原種增加10-12％；玉米同源四倍體籽粒胡蘿卜素含量比二倍體原種增加43％。7.2染色體畸變-