第十一章 遗传与发育打印稿.pptx

KeyConcepts Differentiation 分化 Thechangesincellshapeandphysiologyassociatedwiththeproductionofthefinalcelltypesofaparticularorganortissue Determination 决定 Theprocessofcommitmentofcellstoparticularfates Determinationprecedesdifferentiation 第十一章发育遗传学DevelopmentalGenetics 第一节基因组等价性GenomeEquivalence Genomeequivalence eachsomaticcellofamulticellularorganismcontainsacompletesetofgeneticinformationTotipotent 全能性 Developmentineukaryotesischaracterizedbytheselectiveexpressionofgenesetsincellswithequivalentgenomes 第二节线虫的发育DevelopmentinC elegans 1 OverviewofC elegansdevelopmentCaenorhabditiselegansLivesinsoil andfeedsonsoilbacteria Adultsareabout1mmlong matureinabout2days 2n 12 XXXO contain 15000genesTheadulthermaphrodite 雌雄同体 consistsof959somaticcells andabout2000germcells 2 Theexactcelllineage 细胞谱系 fromfertilizedeggstoadulthasbeenmapped 3 Programmedcelldeath PCD 细胞程序性死亡 isgeneticallyregulatedandisrequiredfornormaldevelopment Programmedcelldeathorapoptosisisanormalprocesswherebycellsundergoacharacteristicseriesofevents suchaschromosomecondensationandblebbingoftheplasmamembrane thatleadtotheirdeath 131of1090inhermaphrodite and147of1178inmaledieduringdevelopmentThetimeatwhichagivencelldiesissameTheidentityofthecellsthatdieissame ControlofprogrammedcelldeathinC elegans Binaryswitchgenes Theced 9geneofC eleganshasahumanhomolog 同源基因 thebcl 2proto oncogene 原癌基因 whichplaysaroleinprogrammedcelldeathinmammals 第三节果蝇的胚胎发育EmbryonicDevelopmentinDrosophila 1 OverviewofDrosophiladevelopmentLifecycleFivedistinctphases theembryo threelarval 幼虫 stages thepupal 蛹 stageEarlystagesofembryonicdevelopmentTheDrosophilaegghasanumberofstructuresthatdelineatetheanterior 前 posterior 后 dorsal 腹 ventral 背 regions 2 Maternal effectgenes 母体效应基因 andzygoticgenes 合子基因 interacttodeterminethebasicbodyplan Maternal effectgenesSegmentationgenes 分节基因 gapgenespair rulegenessegmentpolaritygenesHomeoticgenes 同源异形基因 acascadeofcontrol 3 Maternal effectgenes Maternal effectgenesarethosewhosegeneproducts mRNAandproteins aredepositedinthedevelopingeggduringoogenesis 卵子形成 Theproductsofmaternal effectgenesareoftendistributedinagradientorconcentratedinspecificregionsoftheeggs TheanteriorgenesbcdgeneThebcdproteinisatranscriptionfactorsthatbindstotheupstreamregulatoryregionofhunchback oneofthefirstzygoticgenestobeactivatedearlyindevelopment whichisexpressedinthenucleiintheanteriorhalfoftheembryo Inembryosderivedfrombcd mothers theanterior headandthoracic segmentsdonotform Coordinatedactionofbcdandnanosproteinsproducestheanterior posterioraxisoftheearlyembryo nanosThenanosproteinpreventsthetranslationofanyhunchbackmRNA Theposteriorgenes GapgenesThetranscriptionofthegapgenesisactivatedorinactivatedbyproductsofmaternal effectgenesThetranscriptionofgapgenesdividestheembryointoaseriesofbroadregions roughly thehead thorax andabdomen Todate allgapgenesthathavebeenclonedencodetranscriptionfactorswithzincfingerDNA bindingmotifs 锌指结构 Pair rulegenesThepair rulegenesdividethebroadregionsestablishedbythegapgenesintoaboutonesegmentwide Atleasteightpair rulegenesacttodividetheembryointostripes andtheboundariesofthesestripesoverlap Manypair rulegenesencodetranscriptionfactorscontaininghelix turn helixhomeodomain 同源结构域 Antennapediacomplex ANT C labial lab antennapedia antp sexcombreduced scr deformed dfd proboscipedia pb Bithoraxcomplex BX C Ultrabithorax ubx AbdominalA adbA AbdominalB adbB Mutationsinhomeoticgenesoftencausetransformationofonebodypartintoanother homeosis Characteristicsofhomeoticgenes Encodetranscriptionalfactors60aminoacidsconstituteaDNA bindingdomain homeodomain180bphomologoussequence homeobox codingforhomeodomainSimilarsequencehavebeenfoundinthegenomesofothereukaryoteswithsegmentedbodyplan mice human 第四节性别决定与分化SexDeterminationandDifferentiation 1 DrosophilasexdeterminationInDrosophila thechromosomalbasisofsexdeterminationisduetotheratioofXchromosomestosetsofautosomes 常染色体套数 X Aratioregulatesexpressionofthesexlethal sxl gene Sxltriggersacascadeofalternativesplicing 可变剪接 2 Sexdeterminationinmammals Primarysexdetermination 初级性决定 TheYchromosomedeterminesmalenessTestis determiningfactor TDF 睾丸决定因子SexdeterminationregionoftheY SRY TheSRYproteinisatranscriptionfactor HumanaberrantsexualdevelopmentKlinefeltersyndrome XXY 2 1000Turnersyndrome XO 1 3000XXX 1 1200XYY Secondarysexdetermination 次级性别决定 Sexualdifferentiation 性别分化 sexreversal 性反转 3 Othersexdeterminations Temperaturevariationcontrolssexdeterminat