基因流动和和GM作物的环境风险评估

1、GeneflowandenvironmentalriskassessmentofGMcrops基因流动和和GM作物的环境风险评估,AlanRaybould,EcologicalSciences,Syngenta阿兰.雷博德,生态学部,Syngenta公司,Outline概要,Whatisgeneflow?MethodstoestimategeneflowRegulatoryriskandenvironmentalriskHazardandexposureGeneflowinenvironmentalfateGeneflowandweedinessGeneflowandgeneticresour

2、cesDatarequirementsforriskassessmentRiskassessmentframework,什么是基因流动?评估基因流动的方法调整风险和环境风险危害和暴露在环境归趋中的基因流动基因流动和杂草基因流动和基因资源风险评估所需的数据风险评估框架,Whatisgeneflow?什么是基因流动?,EncyclopaediaBritannica“Introductionofgeneticmaterial(byinterbreeding)fromonepopulationofaspeciestoanother,therebychangingthecompositionoftheg

3、enepoolofthereceivingpopulation.”不列颠百科全书“基因(由杂交繁殖产生的)由一个种群传向另一个种群,从而改变了接受基因种群的基因组成”,Whatisgeneflow?什么是基因流动?,AnaturalphenomenonhelpsmaintaingeneticvariationOccurswithinandbetweencrops,weedsandwildplantsInplants,themainagentsofgeneflowarepollenandseeds基因流动是自然现象能够帮助维持基因变化基因流动发生在作物杂草和野生植物之间.在植物中基因流动的主要载

4、体是花粉和种子.,Geneflowviapollen以花粉为载体的基因流动,PlantshavemechanismstodispersepollenSomespeciesusewindSmall,unspectacularflowersProducelargeamountsofpollen,植物有传播花粉的机制一些物种利用风作为传播花粉的媒介:小且不引人注意的花产生大量花粉,Conifers松树TreesGrasse草,Geneflowviapollen以花粉为载体的基因流动,SomeplantsuseanimalvectorsInsects(birds,bats,othermammals,s

5、lugs)Attractanimalsbycolour,scentandrewards(pollenandnectar),一些植物以动物为花粉的载体昆虫(以及鸟类,蝙蝠,其他哺乳类动物,蛞蝓)以颜色,花香和花粉,花蜜来吸引动物,Beeorchidmimicry蜜蜂兰拟态,Dogrosecolour,pollen,Geneflowviapollen以花粉为载体的基因流动,Someplantspreventorreduceself-fertilisation某些植物防止,减少自我受精,Hopmaleandfemaleflowersonseparateplants蛇麻草-雌雄异体,Maizesepa

6、ratemaleandfemaleflowersonsameplant玉米-雌雄同体但异花,Brassicaself-incompatibilit芸苔自花不育,Geneflowviaseed以种子为载体的基因流动,ManymechanismstopromoteseeddispersalWindStructurestokeepseedsairborneAnimalsStructurestocatchthefurofanimalsFruits+hardseedcoattoprotectseedsfromdigestionManWeedsmimiccropsDispersalintimeDorman

7、cy,有许多促进种子传播的机制风使种子在空气中传播动物种子附着在动物的皮毛上果实和种皮能防止种子被消化人类野草和作物相似及时传播冬眠,Geneflowviaseed以种子为载体的基因流动,Dandelionwind蒲公英风,Falseoatmimicry伪燕麦模仿,Tomatofruitandhardseeds番茄果实和种皮,Goosegrassanimalfur牛筋草动物皮毛,Geneflowanddispersal基因流动和分散,GeneflowanddispersalarenotthesamePollenmusteffectfertilisationSeedsmustgerminatea

8、ndproducereproductiveplantsDispersal=potentialgeneflowFertilisationandproductionoffertileplants=actualgeneflow,基因流动和分散是不同的花粉必须能够受精种子必须发育并长成有繁殖能力的植株分散=潜在的基因流动植株的受精和繁殖=真正的基因流动,Methodstoestimategeneflow,1Directmethods:estimatecontemporarydispersal;makefewassumptions;weakatdetectingrare,long-distancedis

9、persal2Indirectmethod:estimatesofgeneflowovermanygenerations;detecteffectsofrare,long-distancedispersal;relyon(untestable)assumptionsaboutdemography,评测基因流动的方法,评测基因流动的方法,1直接方法:估测同一代传播的花粉;做出一些假设;缺点是检测率低和无法估测长距离花粉传播2间接方法:可以估测不同代传播的花粉;可以检测不常见的作用和长距离的花粉传播;依赖于统计学的假设,Regulatoryriskandenvironmentalrisk管理上的风

10、险和环境风险,GeneflowmayleadtounintendedpresenceoftransgenesPresencemaycontraveneregulationsorpermitconditionsUnapprovedEventsoutsidefieldtrialsEventsapprovedforanimalfeedinhumanfoodchainApprovedEventsabovethresholdsinunlabelledbatchesCo-existenceofGMandorganicfarming,基因流动会导致转基因的意外出现这种意外会违背规律和允许的条件在农田外未经允

11、许的转基因状况在动物饲料中允许的基因出现在人类食物中在阈值之上的基因出现在未被标记的组中GM和有机作物共存,Regulatoryriskandenvironmentalrisk管理上的风险和环境风险,CanleadtofinesandcompensationtoaffectedpartiesPresenceofthegenemayhavenoeffectonsafetyAregulatory(oreconomic)risk,notanenvironmentalrisk会导致对背影响部分的补偿基因的出现可能不会对安全产生影响管理上的(或者是经济)风险,而不是环境风险,Geneflowandenv

12、ironmentalrisk基因流动和环境风险,GeneflowisanaturalphenomenonTheprocessdoesnotconstituteariskinitselfTheriskresultsfromanyharmfulpropertiesofthegeneHazard=harmfuleffectofthegeneExposure=presenceofthegenewhereitcancauseharmGeneflowispartoftheexposureassessment,基因流动是一种自然现象这个过程本身不会产生风险而风险是由基因的负面性质产生的危害性=基因的负面作用

13、暴露=基因的出现导致危害的产生基因流动是暴露评估的一部分,Geneflowandenvironmentalfate基因流动和环境归趋,Environmentalfateistheconcentration,distributionandpersistenceofachemicalintheenvironmentAfateassessmentiscarriedoutforGMproteinsDetermineswhichorganismsareexposedtotheproteinSeeExposureCharacterizationthisafternoon环境归趋是某种化学物质在环境中的浓度

14、,分布和持续性.GM蛋白的归趋评估确定哪些生物体暴露于GM蛋白参见今天下午的暴露特性,Geneflowandenvironmentalfate基因流动和环境归趋,Geneflowcandispersetheproteintoothervarietiesofthesamecrop(crop-to-crop)tofollowingcrops(viadormancyandvolunteering)tonon-agriculturalhabitats(invasivenessorweediness)tootherspecies(wildplants,horizontalgenetransfer)基因流

15、动是蛋白分散分散到同一作物的不同亚种中(作物-作物)分散到其他作物中(通过休眠体和自生体)分散到非农业环境中(入侵或杂草)分散到其他物种(野生植物,横向基因转移),Environmentalfate:crop-to-cropgeneflow环境归趋:作物-作物基因流动,ForEventsforcommercialsale,itisassumedthatcrop-to-cropgeneflowwilloccurSporadic,lowfrequenciesoftransgenesinnon-GMcropsCalled“adventitiouspresence”Environmentalsafet

16、yassessmentwillcoverthispresenceAssessmentforintendedcultivationisworst-caseIntendedconcentrationofproteinadventitiousconcn,对于商业作物,可能会发生作物-作物基因流动在非GM作物中转基因发生的频率低叫做“偶然发生”环境安全评估包含耕作评估是最坏的例子蛋白浓度外来浓度,Environmentalfate:crop-to-cropgeneflow环境归趋:作物-作物基因流动,Mayneedstudiestoshowthatproteindoesnotaffectpropert

17、iesofcommoditiesE.g.,maizeexpressingGMalpha-amylaseNotoxicitytohumans,farmanimalshybridsgototierII可以通过一系列测试来进行评估第一阶段:实验室方法测试杂交如果没有杂交,停止测试;有则进入第二阶段,Handpollination人工授粉,Embryorescue胚胎援助,Geneflowtowildrelatives基因流向野生亲缘植物,TierII:Testfor“spontaneous”hybridisation(laborfield)Ifnohybrids,stoptesting;hybrid

18、sgototierIII第二阶段:自然发生假设测试(实验室或田间)如果没有杂交,停止测试;有则进入第三阶段,Geneflowtowildrelatives基因流向野生亲缘植物,TierIII:Searchfornaturally-producedhybridsinfieldNohybrids,stoptestingIfhybrids,needtoassesshazard,第三阶段:田间自然发生杂交的搜索如果没有杂交,停止测试如果有杂交,需要对危害性进行评估,Riskassessmentframework风险评估框架,TestthatthebiologyoftheGMplantisnotsign

19、ificantlydifferentfromanon-GMequivalent(Usedinthehazardassessmentforweediness)Ifnodifferent,useinformationonthebiologyofthenon-GMplanttoassessgeneflowparameters:Adventitiouspresence(crop-to-crop)VolunteerpopulationsFeralpopulationsGeneflowtowildplantsandHGT,GM植株生物学特征测试与非GM植株生物学特征测试没有显著区别(应用于杂草化危害性评估

20、)如果没有区别,可以应用非GM植株生物学信息来评测基因流动参数:偶然发生(作物-作物)自然生长植物种群野生种群基因流向野生亲缘植物和HGT,Riskassessmentframework风险评估框架,UsuallysufficientinformationinpublishedliteratureIfnot,datacanbeobtainedbysimpleexperimentsUsethisinformationtoconfirmthatexposuretoGMproteinsviageneflowwillbenohigherthanthatviacultivationIfso,andift

21、oxicityriskfromcultivationisacceptable,toxicityriskviageneflowwillbeacceptable,通常来说发表在文献上的信息是足够的如果信息不充分,可以通过简单的实验来采集数据通过这些信息可以断定通过基因流动对GM蛋白的暴露不高于通过耕种对GM蛋白的暴露如果是这样,而且如果耕种的毒性风险是可以接受的,那么基因流动的毒性风险也是可以接受的,Riskassessmentframework风险评估框架,IfbiologyofGMplantisnotsignificantlydifferentfromnon-GMequivalent,theweedinessriskfromvolunteersandferalpopulationsisacceptableHowever,extraexperimentsmayberequiredtoassesstheweedinesshazardofwildrelativescontainingthetransgene,如果GM植株的生物学特性和非GM植株并没