论文标题:元宝山冷杉种群的遗传多样性研究
Genetic Diversity in Population of Abies Yuanbaoshanensis Revealed by AFLP Markers
论文作者 王燕
论文导师 唐绍清,论文学位 硕士,论文专业 生态学
论文单位 广西师范大学,点击次数 104,论文页数 60页File Size3578k
2002-04-01论文网 http://www.lw23.com/lunwen_80711907/ AFLP;元宝山冷杉;遗传多样性
AFLP;Abies yuanbaoshanensis;Genetic diversity
元宝山冷杉是松科冷杉属的常绿针叶乔木，是20世纪70年代发现的新种，它是世界上仅产于广西融水县北部元宝山的残遗濒危种，已被列为一级保护的濒危植物。元宝山冷杉是第四纪冰期幸存下来的濒危物种，在广西的发现，对于研究我国南方古代植物区系的发生和演变，以及古气候、古地理有重要意义，特别是对第四纪冰期气候的探讨有学术价值，它是研究气候变化和植物变迁的依据，是活化石。元宝山冷杉是具有重大科学价值的类群，目前它却处于高度濒危极待保护状态，要有效保护和挽救这一作为我国生物多样性的关键类群，选择合适的方法来研究其遗传多样性是非常必要的。首先，物种的遗传多样性是长期进化的结果，是其生存和发展的前提，对遗传多样性进行研究可以为分析濒危物种或种群的进化潜力和未来命运提供重要资料；其次，遗传多样性是保护生物学研究的核心之一，不了解种内遗传变异大小、时空分布及其与环境条件的关系，就无法采用科学有效的措施来挽救濒于灭绝的物种、保护受到威胁的物种，对珍惜濒危物种制定合理的保护方针和策略，有赖于对物种遗传多样性的认识。 本研究选用一种高效的检测遗传变异的分子标记——AFLP技术来分析元宝山冷杉种群的遗传多样性，旨在了解该种群在分布区内的遗传变异水平和遗传结构情况；研究结果将有助于更清楚地认识这一濒危类群的生存潜力和濒危程度，而且可以为制定何种挽救和保护措施提供科学的依据。 本研究选用了元宝山冷杉种群内43株大树的嫩叶作为研究材料，用CTAB法从这些植物中提取到了质量高的DNA，结合DPS纯化系统纯化，有效地除去植物叶片中多糖或多酚等不纯物；然斤将纯化后的基因组DNA用于进行AFLP的各步反应；用荧光染料标记EcoRI引物，从24组引物对中筛选出4组引物对进行AFLP扩增；4个引物组合对43个样的总DNA进行扩增，共得到261条DNA扩增带，。统计这些AFLP表型带标记，用POPGENE软件计算各种多样性数据(PPB值为51％，Shannon多样性指数为0.086，Nei"s基因多样性值为0.151)：用NTSYS软件计算各个样品间的相似性系数，并用UPGMA法基于相似性系数进行聚类分析，构建树状图，它们可反映出元宝山冷杉种群内个体间的遗传关系。 研究结果表明：AFLP方法是一种十分有效的检测种群遗传多样性的分子标记，既具有可靠性又有方便高效性；元宝山冷杉种群的遗传多样性水平很低，种群内各个个体间的相似性系数很大，遗传关系很近，无明显的遗传分化，这说明该种群的适应能力差、进化潜力有限，濒危程度很高；若要保护或保存这个物种的遗传资源，建议应该选择种群内尽可能多的个体进行保护。
Abies yuanbaoshanensis is a Guangxi endemic and endangered evergreen coniferous arbor,listed in the Red Data Book of plant in P.R.C,being one of the stated-proteced first-class rare and endangered plants. It is distributed only in Yuanbaoshan mountain in northern Guangxi. Abies yuanbaoshanensis having survived the Quaternary Period Ice-age is significant not only to studying the occurrence and evolution of the Chinese ancient south plant flora but also to the ancient climate and geography. Especially,it has the scientific value of inquiring into the climate of the Quaternary Period Ice-age and is called live fossil because it could provide the basis for studying the climatic change and the changes of plant. Endangered Abies yuanbaoshanensis will probably have been extinct,so it very necessary to studying its genetic diversity with a proper way in order to save this key group of biological diversity in China.In the present study,AFLP(amplified fragment length polymorphism) markers was used to examine population of Abies yuanbaoshanensis in order to understand the level of population genetic variation and genetic structure. The result would help to evaluate its evolutionary potentiality and the degree of being endangered and could provide scientific basis for making right protection strategy .High-quality DNA was extracted using CTAB method from those tender leaves of forty-three fully-developed trees in population Abies yuanbaoshanensis. Primers of EcoRI were signed with fluorescent dye and four pairs of primers were selected from twenty-four pairs. 261 DNA fragments were generated by the four pairs of primers in forty-three individuals sampled. Percentage of polymorphic bands is 51%,the value of Shannon index(I) is 0.086 and Nei"s gene diversity(h) is 0.151. The genetic data were analyzed using the POPGENE version 1.31 and the NTSYS version 2.02 and dendrograms were constructed using similarity coefficient and UPGMA clustering method. This study showed that population genetic diversity was much lower than other Gymnosperm and there was no distinct genetic differentiation among individuals in this population. In order to protect or preserve its genetic resource,it is suggested that the most individuals in the population should be selected as we can.
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