【作者】 单体锋；

【导师】 逄少军；

【作者基本信息】 中国科学院研究生院（海洋研究所） ， 海洋生物学， 2009， 博士

【摘要】 利用AFLP标记对海带在太平洋西北沿岸的6个主要栽培品系和6个野生地理隔离种群进行遗传多样性和亲缘关系分析。通过10对选择性引物总共检测到547个位点。在品系和种群水平,多态性位点比例(P),基因多样性(H)和香农指数(I)在大连野生种群中最高(P: 59.05%; H: 0.2057; I: 0.3062),而在连江栽培品系中最低(P: 9.87%; H: 0.0331; I: 0.0497)。在物种水平(即对所有品系和种群来说),P, H和I的值分别是85.01%,0.1948和0.3096。以个体间的相似系数(Dice)和种群间的遗传距离为基础,用非加权类平均法(UPGMA)分别构建个体和种群间的系统树图。AMOVA分析显示,大部分的遗传变异(60.21%)存在于品系和种群间,少部分(39.79%)存在于品系或种群内。遗传分化系数GST的值是0.6226,与FST的值(0.6021)非常接近,基因流(Nm)的值是0.1515,这三个值表明种群(品系)间存在高度的遗传分化。Mantel检验发现6个野生种群的遗传距离或遗传分化与地理距离呈正相关性(相关系数分别是r=0.8870, P=0.007和r=0.7962, P=0.011),符合“距离隔离(isolation by distance, IBD)”模型。总体来说,种群(品系)内的遗传多样性处于低到中等水平(大连种群除外),而它们之间的遗传分化程度非常高。用AFLP和微卫星标记对裙带菜配子体克隆单一交配组合的孢子体后代的遗传一致性进行分析。在这项研究中,建立了2个配子体克隆单一交配系(M1和M2),2个自交系(S1和S2)并采集1个野生种群(W)。11组AFLP引物总共检测到318个位点。M1, M2, S1, S2和W的多态性位点比例分别是4.7%,0.3%,17.9%,16.4%和36.5%。M1和M2个体间的遗传相似度(95.6-100%)要高于S1和S2(87.7-98.4%)以及W(81.5-92.1%)。在微卫星分析中,用了6个位点。M1在其中的5个位点基因型一致,而在Up-AC-2B2位点显示出不同的基因型。M2在所有6个微卫星位点的基因型都一致。而S1, S2和W都在2个以上的位点检测到不同的基因型。总之,AFLP与微卫星的分析结果一致,即配子体克隆单一交配组合的孢子体后代呈现高度遗传相似性,但也存在细微的差异。对中国羊栖菜主产区浙江省洞头县的12个羊栖菜养殖品系的重要形态特征进行了比较研究,并利用AFLP技术对一个典型养殖种群的遗传多样性进行了分析。结果显示,这12个品系在全长、全湿质量、侧枝长、侧枝湿质量、侧枝密度等方面存在显著或极显著差异(P<0.05或P<0.01)。8组AFLP引物在这个典型养殖种群中扩增出198个片段,其中多态性片段为166个,多态性位点比例为83.8%。根据个体间的遗传距离,以UPGMA法构建了个体间的系统树图,27个羊栖菜个体聚为一枝,作为对照的铜藻为另一枝。本研究从形态和DNA分子水平说明了浙江洞头羊栖菜养殖种群具有高度遗传多样性。更多还原

【Abstract】 The genetic diversity and relationships of six representative cultivars and six geographically isolated wild populations of Saccharina japonica (J.E. Areschoug) C.E. Lane, C. Mayes, Druehl & G.W. Saunders along northwest coasts of the Pacific were investigated using amplified fragment length polymorphism (AFLP) markers. A total of 547 bands were generated across all samples by ten primer combinations. At the population or cultivar level, the percentage of polymorphic loci (P), gene diversity (H) and Shannon’s information index (I) was highest in the Dalian population (P: 59.05%; H: 0.2057; I: 0.3062) and lowest in the Lianjiang cultivar (P: 9.87%; H: 0.0331; I: 0.0497). At the species level, P, H and I was 85.01%, 0.1948 and 0.3096, respectively. Two UPGMA dendrograms were constructed respectively based on the Dice similarity coefficients among individuals and genetic distances among populations and cultivars. Analysis of molecular variance (AMOVA) revealed that a higher portion (60.21%) of variations resided among cultivars and populations, while a lower portion (39.79%) within cultivars and populations. The GST value was 0.6226, consistent with FST (0.6021), and the gene flow (Nm) was 0.1515, indicating strong genetic differentiation among cultivars and populations. The Mantel test suggested that genetic distance or genetic differentiation was positively correlated with geographic distance (r=0.8870, P=0.007 and r=0.7962, P=0.011, respectively) in the six wild populations, agreeing with the IBD (isolation by distance) model. On the whole, low to moderate genetic diversity within cultivars or populations (except Dalian population) and high genetic differentiation among cultivars and populations were detected.AFLP and microsatellite markers were adopted to assess the genetic identity of the sporophytic offspring derived from mono-crossing of gametophyte clones of Undaria pinnatifida. In this investigation, two mono-crossing lines (M1 and M2) and two selfbreeding lines (S1 and S2) were constructed, and a wild population (W) was collected. A total of 318 loci were detected using eleven AFLP primer combinations. The percentage of polymorphic loci in M1, M2, S1, S2 and W was 4.7%, 0.3%, 17.9%, 16.4% and 36.5%, respectively. The genetic identity in M1 and M2 (95.6-100%) was higher than that in S1, S2 (87.7-98.4%) and W (81.5-92.1%). In microsatellite analysis, six loci were used. For either M1 or M2, almost identical genotype was detected at every locus except for M1 at locus Up-AC-2B2, which differentiated M1 into two kinds of genotypes. For S1, S2 or W, different genotypes were detected at two or more loci. In conclusion, high genetic identities were found in sporophytic offspring derived from mono-crossing of gametophyte clones of U. pinnatifida by means of both AFLP and microsatellite markers, however, subtle genetic variations were also detected.Twelve strains and a representative farmed population of Hizikia fusiformis were sampled from its principal cultivation ground, i.e. Dongtou county, Zhejiang province. Important characteristics of these strains were compared and genetic diversity of the population was analyzed using AFLP technique. Morphological analysis revealed significant differences among these 12 strains in terms of total length, total wet weight, branchlet length, branchlet wet weight and brachlet density(P<0.05 or P<0.01). In AFLP analysis, a total of 198 fragments were amplified in twenty-seven individuals of the representative population by means of eight primer combinations, of which 166 were polymorphic. The percentage of the polymorphic fragments was 83.3%. A UPGMA dendrogram was constructed based on the genetic distances among the individuals, in which twenty-seven individuals of H. fusiformis clustered into one clade and the control individual of Sargassum horneri clustered into another one. In conclusion, high genetic diversity was revealed in the farmed population of Hizikia fusiformis from both morphological and molecular level.更多还原