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ID:41239553
大小:1.57 MB
页数:30页
时间:2019-08-20
《Maintenanceofvariation变异的维持》由会员上传分享,免费在线阅读,更多相关内容在教育资源-天天文库。
1、GeneticVariation-ThefuelofnaturalselectionCampbelletal,chapter23PopulationsarepolymorphicNaturevs.NurtureSourceofvariationMaintenanceofvariationPopulationsarepolymorphicNaturevs.NurtureSourceofvariationMaintenanceofvariationPolymorphicpopulationsExampl
2、e:DarwinfinchesonGalapagosPolymorphicpopulationsExample:LazulibuntingPolymorphicpopulationsExample:SwallowtailbutterflyPopulationsarepolymorphicNaturevs.NurtureSourceofvariationMaintenanceofvariationNaturevs.NurturePhenotypicExpressionProteinGenome(blu
3、eprint)NatureEnvironmentNurtureIfoundthegenethatmakesusbelievealltraitsarebasedongenesNaturevs.NurtureGeneChromosomeGenomeGenepoolNaturevs.NurtureDiploidyThereare2copiesofeachgeneFatherMotherOffspring2identicalcopies=homozygotFatherMotherOffspring2diff
4、erentcopies=heterozygotNaturevs.NurtureGenotypeismorevariablethanphenotypeOnlygeneticvariationcountsforevolutionNaturevs.NurtureHowtoseparatethetwo?Example:AltitudinalgradientCommonGardenExp.GeneEnvironmentMixtureofbothPopulationsarepolymorphicNaturevs
5、.NurtureSourceofvariationMutationRecombinationMaintenanceofvariationSourceofGeneticVariation1.MutationChangein:DNAsequenceChromosomestructureNumberofChromosomesDueto:CopyingErrorsEnvironmentalfactorsSourceofGeneticVariation2.RecombinationReshufflingofc
6、hromosomesduringreproductionCrossingoverABCABCABCABCPopulationsarepolymorphicNaturevs.NurtureSourceofvariationMaintenanceofvariationSelectionHeterosisMaintenanceofVariation1.StabilisingselectionFavoursmeanovertailLossofvariationMaintenanceofVariation1.
7、StabilisingselectionExample:DarwinFinchesBillsizeForagingefficiencyMaintenanceofVariation2.DirectionalselectionOnetailisfavouredovertheotherTraitischangingovertimeMaintenanceofVariation2.DirectionalselectionExample:Heliconiusbutterflyonpassionflowervin
8、esPlant:ToxinInsect:EnzymesPlant:FalseeggsLeadstoanarmsracebetweenplantandinsectMaintenanceofVariation2.DirectionalselectionThearmsraceidealeadtoamoregeneralhypothesis:RedQueenHypothesis‘Ittakesyoualltherunningtostayinplace’Maintenanceo
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