Population Morphology And Genetics Of Scapharca Subcrenata Near The Coasts Of Shandong Peninsula

Scapharca subcrenata,belongs to the family Genus Scapharca,widely distributedin different climate,latitude and sea conditions.In China,Scapharca subcrenata is acommercially important species group.This study intends to comprehensive usingmorphology analysis and genetics analysis method to research the populations ofScapharca subcrenata. This study discusses the differences and genetic differentiationbetween different groups of Scapharca subcrenata; systematically analyzes thedifferent groups of Scapharca subcrenata between morphological and geneticdifferentiation; Also reveals the distribution pattern and the history of the groupdynamic, discusses Scapharca subcrenata classification status, population divisionand its formation and maintain the current geographical pattern of the mechanism,trace and to reveal the evolution of species course, further understood mussels kind ofevolution, ecological environment and human activities on the influence and the roleof mussels and make appropriate mussel germplasm resources protection andmanagement measures provides the reliable theory basis for the similar distributionand biological characteristics of other organisms also has important referencemeaning and value.1.Different geographical populations of Scapharca subcrenata, sampled fromdifferent areas a respectively, were studied on the basis of13morphologicalcharacters. Multivariate morphometrics was used to investigate the morphologicalvariations among these populations.(1) For populations of Shandong Peninsula,theresults of cluster analysis and principal component analysis showed that thepopulations from Dongying-Guangrao, Dongying-Hekou,Weifang-Yangkou andWeifang-Dajiawa were morphologically similar, whereas the Yantai-Luyanggangpopulation deviated most. The principal component analysis resulted in threeprincipal components, with the contributory ratios of24.78％，18.53％，and15.40％respectively, and the cumulative contributory ratio was58.70%. The stepwisediscriminant analysis revealed that the eight populations differed significantly inmorphology (P<0.01). The discriminant functions of the eight populations wereestablished, with the discriminant accuracy of70.00％-100％for P1,73.44％-100％for P2, and the average discriminant accuracy of85.20％.(2)For populations indifferent sea areas of China, the results of cluster analysis and principal componentanalysis showed that the populations from Qingdao-Hongdao and Rizhao-Lanshanwere morphologically similar, whereas the Yantai-Luyanggang population andHainan-Sanya population deviated most. The principal component analysis resulted inthree principal components, with the contributory ratios of30.73％,24.59％and12.32％,respectively, and the cumulative contributory ratio was66.40%. The stepwisediscriminant analysis revealed that the six populations differed significantly inmorphology (P<0.01). The discriminant functions of the six populations were established, with the discriminant accuracy of80.00％-100％for P1,79.37％-100％for P2, and the average discriminant accuracy of91.40％. The study made acomparative study of morphological differences among Scapharca subcrenata fromdifferent areas and analyzed the characteristics of intraspecific morphologicaldifferences, providing important scientific knowledge of identification, geneticcharacteristic research and protection&restoration of germplasm resources forScapharca subcrenata’s geographical populations.2.We explored the intraspecific phylogeographic pattern anddispersal patterns inpopulations of Scapharca subcrenata.(1)Sequence variation of the ITS-2(IinternalTranscribed Spacer2) region was analyzed among7populations of Scapharcasubcrenata. The length of sequences is386bp. Base composition in DNA genes:A+T=52.7%，G+C=47.3%. Sequence variation of the ITS-2(Iinternal TranscribedSpacer2) region was analyzed151samples among seven populatins of Scapharcasubcrenata,defining299Conserved sites,81Variable sites,17Parsim-info sites,59Singleton sites,67haplotypes.(2)Sequence variation of the COI(CytochromeOxidase Subunit I)region was analyzed among5populations of Scapharcasubcrenata,defining18haplotypes.The length of sequences is692bp. Three distinctlineages were found, whichmight be isolated and diverged in different marginal seas.There were little geographical differences in haplotype frequencies of the threelineages. Hierarchical molecular variance analysis(AMOVA) and conventionalpopulation FSTcomparisons revealed no significant genetic structure throughout theexamined range, which is inconsistent with previos findings based on themorphological and ecological studies. These results indicated that pelagic larvae canpotentially interconnect distant populations through dispersal,leading to high geneflow among different populations.Through the study of genetic diversity of Scapharca subcrenata group can helppeople more clearly know and understand the existing biological resources status, soas to take the appropriate strategy to the protection and rational utilization of availableresources to provide theoretical guidance. Secondly, in speculation and master groupgenetic variation in the level of genetic differentiation, groups status and relationshipsystem for Marine bivalves of classification research, the system evolution to providea meaningful reference material.