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Bay Scallop Farming Population Genetic Diversity And Genetic Differentiation

Posted on:2005-10-14Degree:MasterType:Thesis
Country:ChinaCandidate:W ZhangFull Text:PDF
GTID:2190360125460619Subject:Marine biology
Abstract/Summary:PDF Full Text Request
Amplified Fragment Length Polymorphism, i.e. AFLP, is a novel molecular markertechnique, having both the high polymorphism of Random Amplified PolymorphicDNA (RAPD) and the reliability of Restrictive Fragment Length Polymorphism(RFLP). It has a good applied prospect considering the fact that it has been used tomany aspects including the analysis of genetic structure and genetic diversity, thelinkage map construction and the quantitative trait locus (QTL) mapping, et al.A complete AFLP marker system has been established in this study. According to thetext of inheritance pattern for AFLP markers, AFLP was a powerful, sensitive andrapid technique which permitted inspection of polymorphism at a large number of lociwithin a short period of time. All the examined AFLP markers appeared to displaymore dominant segregation patterns than that of RAPD. With the test ofpolymorphism for AFLP markers, total 401 polymorphic loci were amplified using 7primer combinations. On average, 57.3 polymorphic bands are amplified by oneprimer combination. The detected fragments are from 100bp to 800bp.In this paper, the genetic structure and genetic diversity of four cultured populationsof Argopecten irradians were analyzed using AFLP technique. Eighty individualsfrom the four populations (twenty individuals per population) were analyzed by usingseven primer combinations. The mean percentages of polymorphic loci of the fourpopulations were 41.1765 % (PA), 48.8235 % (PB), 49.2914 %( PC), and 38.2353%(PD) respectively. The average heterozygosities (H) of them were 0.1618, 0.1878,0.1886 and 0.1265 respectively. Genetic distance among the 4 populations ranged - 3 -张雯 海湾扇贝不同养殖群体遗传多样性'遗传分化的研究 硕士学位论文from 0.1188 to 0.0941. Dendrogram was constructed based on the genetic distanceindex using UPGMA method. The coefficient of inbreeding (Fst) among the fourpopulations is 0.1883, which means that 18.83% genetic variation of the wholepopulation comes from the genetic differences among the four populations. Thephylogenetic trees of four populations suggested that,like the distances, PApopulation was closer to PB population and they were clustered together. PCpopulation and PD population were clustered into another group. The higher values ofheterozygosities and proportions of polymorphic loci of the four populations indicatedthat the Argopecten irradians cultured in China was in an available condition withhigher genetic diversity.Comparison of the two techniques, AFLP and RAPD, used in the study of geneticdiversity and genetic structure between populations of Argopecten irradians has beentaken. Eighty individuals from the four populations (twenty individuals per population)were analyzed using seven AFLP primer combinations and twenty RAPD primersrespectively. AFLP and RAPD banding patterns were transformed into binary data ofpresence–absence and matrices were processed by TFPGA program. The AFLPmarker system revealed lower polymorphism information content (PIC) and effectivenumbers of alleles per locus (Ne) than that of RAPD. But it has a much higherpolymorphism banding patterns and assay efficiency index. The mean proportion ofpolymorphic loci of the four populations and the average expected heterozygosities (H)of them were accordant as revealed by AFLP and RAPD respectively. And thedendrograms were constructed based on the genetic distance index using UPGMAmethod. The phylogenetic tree of four populations suggested that,like the distances,PA population is closer toPB population. PC population and PD population wereclustered into another group. The trend of the two dendrograms is same but thegenetic distance is different. Both AFLP and RAPD techniques have the same trend ingenetic parameters which indicated that the results got by AFLP and RAPD werehighly correlated. The results indicated that both AFLP and RAPD techniques areuseful...
Keywords/Search Tags:AFLP, RAPD, Molecular marker, Genetic diversity, Argopectenirradians.
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