Smith12 framentary mtDNA

线性线粒体DNA

GBE

FirstCompleteMitochondrialGenomeSequencefromaBoxJelly shRevealsaHighlyFragmentedLinearArchitectureandInsightsintoTelomereEvolution

DavidRoySmith1,*,EhsanKayal2,AngelA.Yanagihara3,AllenG.Collins4,StacyPirro5,andPatrickJ.Keeling1

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CanadianInstituteforAdvancedResearch,DepartmentofBotany,UniversityofBritishColumbia,Vancouver,CanadaDepartmentofInvertebrateZoology,NationalMuseumofNaturalHistory,SmithsonianInstitutionBekesyLaboratoryofNeurobiology,Paci cBiosciencesResearchCenter,UniversityofHawaiiatManoa

NationalSystematicsLaboratoryofNOAA’sFisheriesService,NationalMuseumofNaturalHistory,SmithsonianInstitutionIridianGenomes,Inc.

*Correspondingauthor:E-mail:smithdr@dal.ca.Accepted:20November2011

SequencedatafromthisarticlehavebeendepositedinGenBankundertheaccessionnumbers:JN642329–JN642344.

Abstract

AnimalmitochondrialDNAs(mtDNAs)aretypicallysinglecircularchromosomes,withtheexceptionofthosefrommedusozoancnidarians(jelly shandhydroids),whicharelinearandsometimesfragmented.Mostmedusozoanshavelinearmonomericorlinearbipartitemitochondrialgenomes,butpreliminarydatahavesuggestedthatboxjelly sh(cubozoans)havemtDNAsthatconsistofmanylinearchromosomes.Here,wepresentthecompletemtDNAsequencefromthewingedboxjelly shAlatinamoseri(the rstfromacubozoan).Thisgenomecontainsunprecedentedlevelsoffragmentation:18uniquegenesdistributedovereight2.9-to4.6-kblinearchromosomes.Thetelomeresareidenticalwithinandbetweenchromosomes,andrecombinationbetweensubtelomericsequenceshasledtomanygenesinitiatingorterminatingwithsequencesfromothergenes(themostextremecasebeing150ntofaribosomalRNAcontainingthe5#endofnad2),providingevidenceforageneconversion–basedmodeloftelomereevolution.Thesilent-sitenucleotidevariationwithintheA.moserimtDNAisamongthehighestobservedfromaeukaryoticgenomeandmaybeassociatedwithelevatedratesofrecombination.

Keywords:Alatinamoseri,Cnidaria,Cubozoa,geneconversion,invertedrepeat,nucleotidediversity.

Introduction

ThearchetypalanimalmitochondrialDNA(mtDNA)isa15-to20-kbcircularmolecule(Boore1999).Medusozoancnidar-ians(jelly shandhydroids)areamongthefewmetazoanswhosemtDNAsdepartsigni cantlyfromthis‘‘traditional’’architecture.Staurozoans,scyphozoans,andmosthydro-zoanshavelinearmonomericmitochondrialgenomeswithlengthsof;16kb;certainHydraspecieshavemtDNAsthataresegmentedintotwo8-kblinearchromosomes;andallinvestigatedmembersoftheCubozoa(boxjelly sh)havemitochondrialgenomesthataresegmentedintoseverallinearmoleculesof 4kb(WarriorandGall1985;Bridgeetal.1992;EnderandSchierwater2003;KayalandLavrov2008;Voigtetal.2008;Kayaletal.2011).AlthoughnearlycompletemtDNAdataareavailablefromadiversityofmedusozoans(Kayaletal.2011),wholemitochondrialgenomesequences,includingtelomeres,existforjustthree:thescyphozoanAureliaauritaandthehydrozoansHydraoligactisandH.magnipapillata(Shaoetal.2006;KayalandLavrov2008;Voigtetal.2008).Thetelomeresfromeachofthesemitochondrialgenomesformaninvertedrepeat(IR),andinH.oligactisandH.magnipapillata,duplicategenesandpseudogenesarefoundinthesubtelomericregions.Medusozoans,therefore,provideauniqueopportunityforunderstandingtheevolu-tionoflinearchromosomes,telomeres,andmtDNAstruc-turalstability.Toaddressallthreeofthesetopics,wepresentthecompletemitochondrialgenomesequencefrom

ªTheAuthor(s)2011.PublishedbyOxfordUniversityPressonbehalfoftheSocietyforMolecularBiologyandEvolution.

ThisisanOpenAccessarticledistributedunderthetermsoftheCreativeCommonsAttributionNon-CommercialLicense(doc.xuehai.net),whichpermitsunrestrictednon-commercialuse,distribution,andreproductioninanymedium,providedtheoriginalworkisproperlycited.

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GenomeBiol.Evol.4(1):52–58.doi:10.1093/gbe/evr127AdvanceAccesspublicationNovember24,2011

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