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1、AmericanJournalofBotany96(11):20222030.2009.GENETICDIVERSITYOFTHEENDANGEREDANDNARROWENDEMICPIPERIAYADONII(ORCHIDACEAE)ASSESSEDWITHISSR1POLYMORPHISMSSheejaGeorge,2JyotsnaSharma,2,4andVernL.Yadon32UniversityofFloridaNFREC,155ResearchRoad,Quincy,Florida32351US
2、A:and3PacificGroveMuseumofNaturalHistory,PacificGrove,California93950USAHighlyendangeredplantsthatarealsonarrowendemicsaregenerallyfoundtobegeneticallydepauperateandthusareexceed-inglysusceptibletoecologicalandanthropologicalthreatsthatcanleadtotheirextinctio
3、n.PiperiayadoniiisrestrictedtoasingleCaliforniacountywithinabiodiversityhotspot.Weusednineprimerstogenerateintersimplesequencerepeat(ISSR)datatoas-sessitsgeneticdiversityandstructure.Withineachpopulation,99%ofthelociwerepolymorphic,expectedheterozygositywas
4、low,andamajorityofthelociweresharedwithfewotherpopulations.Fortypercentofthetotalvariationcouldbeattributedtopopulationdifferentiationwhiletherest(60%)resideswithinpopulations,andthegeneticdistancesbetweenpopulationswereindependentofthecorrespondinggeograph
5、icaldistances.Highdivergenceamongpopulationsislikelyduetofragmentationandlimitedgeneflow.Eachpopulationcontainsseveralprivateloci,andideally,eachshouldbeprotectedtopreservetheoveralldi-versityofthespecies.BecauseP.yadoniicurrentlyretainsamodestamountofgeneti
6、cvariationamongindividualswithinpopula-tions,preservingandexpandingthehabitatateachsitetoallownaturalexpansionofpopulationswouldbeadditionalstrategiesforitsconservationbeforepopulationsbecometoosmalltopersistnaturally.Keywords:intersimplesequencerepeats;nar
7、rowendemic;Orchidaceae;Piperia;populationgenetics;terrestrialorchid.ExtendingfromsouthernOregonintonorthernMexicoalongbecausetheyarehypervariable,dominantmolecularmarkersthePacificCoastinNorthAmerica,theCaliforniaFloristicthatareespeciallyusefulindetectingdi
8、versityincloselyre-Provinceisazoneofmediterranean-typeclimatewithhighlated,orevenclonal,individuals(Zietkiewiczetal.,1994;Es-plantendemism,whereurbanization,commercialfarming,andselmanetal.,1999).Theyh
