第十八讲- 北大生命科学学院

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1、第十章基因和发育ByHongweiGuo,PekingUniversity,2008.12.24第三讲动物发育的基因调控FruitflyembryodevelopmentDevelopmentInmulticellularorganisms,lifebeginsasasinglecell(zygote).Withfewexceptions,somaticcellscontainthesamegeneticinformationasthezygote.Indevelopment,cellscommittospecificfatesanddifferentiallyexpresssubsets

2、ofgenes.Cellsidentifyandrespondtotheirpositionsindevelopmentalfields.Mostdevelopmentaldecisionsinvolvechangesintranscription.Patternformation（形态建成）IsthedevelopmentofaspatialorganizationoftissuesandorgansPatternformationinanimalsandplantsresultsfromsimilargeneticandcellularmechanismsOccurscontinual

3、lyinplants，butismostlylimitedtoembryosandjuvenilesinanimalsPositionalinformationConsistsofmolecularcuesthatcontrolpatternformationTellsacellitslocationrelativetothebody’saxesandtoothercellsLocation,location,location!!!Temporalinformation:e.g.CO,FT,FLCTiming,timing,timing!!!Development=Real-estate+

4、Stock（发育=房地产+股票）PositionalinformationLocalizationofmRNAs/proteinswithinzygoteestablishespositionalinformation----wheredevelopmentalfieldsbeginasasinglecellFormationofconcentrationgradientsofextracellulardiffusiblemoleculesestablishespositionalinformationinmulticellulardevelopmentalfieldsworksbysig

5、naltransductiondiffusiblemoleculesareknownasmorphogensCytoplasmicdeterminantsDifferentialinductioncytoskeletalelementsPolaritydetermination（极性确定）PatternformationwasextensivelystudiedinthemodelorganismDrosophilamelanogaster---FruitflyThefruitflyissmallandeasilygrowninthelaboratory.Ithasagenerationt

6、imeofonlytwoweeksandproducesmanyoffspring(upto300).Embryosdevelopoutsidethemother’sbody.SequencingofDrosophilagenomewascompletedin2000.DrosophilaasageneticmodelIsolationandcharacterizationofdevelopmentalmutantsNusslein-VolhardandWieschausconcentratedtheireffortsonunderstandingearlyembryogenesis,th

7、eylookedforrecessiveembryoniclethalmutations,andclassifiedthemaccordingtotheirphenotypebeforedeath.Lewisdidpioneeringresearchonlateembryogenesis,whodiscoveredhomeoticmutants-mutantfliesinwhichstructurescharacteri