简介：ThewildPorphyrayezoensiscollectedfromtheQingdaocoastwasusedtoprepareprotoplastsbyenzymedigestion.Thepurelinewasconstructedbycultivatingtheprotoplasts.The18SrDNAoftheP.yezoensispurelinewasclonedandsequenced.Sequenceanalysiswasexecutedforthissequenceandother22sequencesretrievedfromGenBank.Aphylogenetictreewasconstructedusingtheneighbor-joiningmethod.Theresultsrevealedahighdiversityof18SrDNAsequencesingenusPorphyraandtheconsiderablevariationof18SrDNAsequencesindifferentstrainsofthesamespeciesP.yezoensisandP.tenera.Significantdifferenceof18SrDNAsequencewasobservedbetweenP.yezoensisfromQingdao,China,andthetwostrainsofP.yezoensisfromJapan,butthethreestrainsofP.yezoensisformedastablecladeinthephylogenetictree.TheseresultsindicatethepossibilityofinterspeciesandintraspeciesdiscriminationofPorphyrausingthe18SrDNAsequences.