genetic variation in the endangered aquatic fern

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1、BotanicalJournaloftheLinneanSociety,2008,157,657–671.With2figuresGeneticvariationintheendangeredaquaticfernCeratopteristhalictroides(Parkeriaceae)inChina:implicationsfromRAPDandISSRdata112YUAN-HUODONG,JIN-MINGCHEN*,GITURUWAHITIROBERTand1QING-FENGWANG*1LaboratoryofPla

2、ntSystematicsandEvolutionaryBiology,CollegeofLifeSciences,WuhanUniversity,Wuhan430072,Hubei,China2BotanyDepartment,JomoKenyattaUniversityofAgricultureandTechnology,POBox62000-00200,Nairobi,KenyaReceived28March2006;acceptedforpublication20February2008Thegeneticdivers

3、itywithinandamong13populationsoftheendangeredaquaticfernCeratopteristhalictroidesfromfiveregionsofChinawasinvestigatedusingrandomamplificationofpolymorphicDNA(RAPD)andintersimplesequencerepeat(ISSR)markers.Thepercentagesofpolymorphicbandswere61%forRAPDand65%forISSR.Th

4、egeneticdiversityrevealedbyRAPDandISSRvariedgreatlyamongpopulations,withthepercentagesofpolymorphicbandsrangingfrom15%to39%forRAPDandfrom20%to39%forISSR.Analysisofmolecularvarianceshowedthat36%(RAPD)and34%(ISSR)ofvariabilitywaspartitionedamongpopulations.Theresultsi

5、ndicatethatC.thalictroidespossessesanintermediatelevelofgeneticdiversityatthespecieslevelandalowlevelofgeneticdifferentiationamongpopulations.TheManteltestshowednosignificantcorrelationbetweengeneticdistanceandgeographicaldistance(RAPD,r=0.53;ISSR,r=0.18)and,similarl

6、y,averypoorfitbetweenthetwomarkers(r=0.24).Anumberofcauses,includinginbreedingandclonalgrowth,mayhaveledtothelowgeneticdiversitywithinpopulations.AhighgeneflowviasporedispersalinanearlierperiodwhenC.thalictroideswaswidelydistributedinChinaisaplausiblereasonforthelowge

7、neticdifferentiationamongpopulations.StrategiesfortheconservationofthespeciesinChinaarediscussed.©2008TheLinneanSocietyofLondon,BotanicalJournaloftheLinneanSociety,2008,157,657–671.ADDITIONALKEYWORDS:Ceratopteristhalictroides–conservationmanagement–geneticvariation–

8、ISSR–RAPD.INTRODUCTIONIngeneral,mostspecieswithwidedistributionshavehighgeneticdiversity,bothbetweenandwithinThegeneticstructureofpopulati