AFLP标记对日本鳗鲡与中华绒螯蟹种群遗传结构的分析

【作者】 张辛；

【导师】 许晓风； 许璞；

【作者基本信息】 南京师范大学 ， 遗传学， 2008， 硕士

【摘要】 遗传变异的大小及群体遗传结构与一个物种的进化潜力和抵御不良环境的能力密切相关。种群遗传多样性水平、形成机制及时空分布格局的研究,可揭示物种的进化历史,保护并可持续地利用该物种。采用AFLP分子标记技术对东海两个鳗鲡居群(苗种来源于闽江流域的成鳗和长江口捕获的玻璃鳗)共56个个体的遗传多样性水平及居群的遗传结构进行了研究。6对选择性扩增引物共检测到363个位点,其中闽江流域、长江口居群多态位点数分别为228、269,来自闽江流域成鳗群低于来自长江口的玻璃鳗居群(相应的多态位点频率分别为62.81%、74.10%)。与此相应的Nei’s基因多样性系数0.2781、0.3077,Shannon’s信息指数分别为0.4092、0.4493,多态信息指数0.2444、0.2791。分析结果表明:与其它鱼类相比,我国东海这两个鳗鲡居群具有较丰富的遗传变异。两居群的遗传相似度约为0.814,遗传距离为0.2103。根据个体间Nei’s遗传距离矩阵对两居群内个体进行UPGMA聚类分析构建遗传聚类图,结果明显分为两支,表明了它们之间显著的群体分化,这与传统的随机交配理论推测的结果有一定的差距。本实验是应用AFLP技术首次对中国东海日本鳗鲡居群遗传结构状况的研究,对其多态性情况进行了初步分析,并根据得到的生态和遗传的信息对此结果做出解释。对分别来自于长江口外海进行生殖洄游和镇江丹徒进行索饵洄游的两类中华绒螯蟹群体54个个体进行AFLP遗传分析。5对选择性引物共扩增270个位点,其中多态位点数分别为235(长江近海)、231(镇江丹徒)相应多态位点频率分别为(87.03%、85.56%)两群体遗传结构相差不大。通过有效等位基因数(1.5765、1.6214)、Nei’s基因多样性(0.3341、0.3523)、Shannon’s信息指数(0.4937、0.5148)(前者为长江近海,后者为镇江丹徒)表明镇江丹徒群体比长江外海遗传多样性水平稍高。两中华绒螯蟹群体遗传指数如此接近说明虽然生长环境不同且两群体有一定的地理距离,但由于其洄游特性使同一水系的群体间有基因交流的机会使得群体间的遗传分化水平不显著。说明目前自然环境下生活的长江蟹生存条件受人为捕捞、污染等人为原因所造成的影响已较小,较好的维持了蟹苗时的遗传结构状况。本研究利用AFLP技术首次对中国东海日本鳗鲡、长江水系中华绒螯蟹的种群遗传结构进行分析,对其目前的种群遗传状况进行评价,有助于人们更清楚的认识和了解现阶段以上物种的生物资源状况,为管理部门提供采取解决方案的依据。在推测和掌握物种群体内遗传变异水平、种群间的遗传分化状况研究提供参考资料。更多还原

【Abstract】 Genetic variation’s size and community’s genetic structure are closely related with a species’ evolution potential and resistance poor surroundings’ ability.The population genetic diversity levels,the forming mechanism and the space and time distribution pattern research,may reveal the species’ evolution history,to analyze its evolution potential and future destiny provides the important material,will protect and uses the humanity livelihood genetic resources sustainable,saving approaches the species which will exterminate,protecting the threatened species.AFLP analysis was conducted on the two populations of Anguilla japonica from Chinese East Sea(the adult eels whose seeds came from Minjiang River and the glass eels from the Changjiang River).In order to investigate the genetic diversity and the genetic structure of the populations,56 individuals were assessed.Using 6 selective amplify primers,363 discernible DNA fragments loci were distinguished.Of these 228 were polymorphic loci(Minjiang drainage),while 269 were polymorphic loci (Changjiang drainage).The adult eel population was lower than the glass eel population(polymorphic frequencies were 62.81%、74.10%.Nei’s index of phenotypic diversity were 0.2781、0.3077,Shannon index showed 0.4092、0.4493, the heterozygosity were 0.2444、0.2791).The combined results of the analysis of population genetic structure and community investigation suggested:compared with other fishes,the two East Sea eel populations had abundant genetic variation,which indicated that high levels of genetic variation existed in the natural populations of Chinese Anguilla japonica.Genetic similarity of the two populations was 0.814, genetic distance was 0.2103.According to Nei’s genetic distance matrix,and the individuals of the two populations UPGMA genetic clusters were constructed.It showed that there was a high level of genetic differentiation between the two populations,which were discrepant with panmixia theory.This is the first genetic structure research on Anguilla japonica of Chinese East Sea,and it exhibit primary analysis on their diversity.Based on the ecological and genetic information available results,some explains were brought forward.The biochemical genetics in two populations of Eriocheir sinensis collected from Changjiang river’s offshore were analyzed by AFLP(amplified fragments length polymorphism).One population was in the spawning migration and from Zhenjiang Dantu,the other was in feeding migration.54 individuals were assessed using 5 selective amplify primers,270 discernible DNA fragments loci were produced.Of these 235 were polymorphic loci(Changjiang river’s offshore),while 269 were polymorphic loci(Zhenjiang Dantu).The result shows that the two populations genetic viability are similar.The mean effective number of alleles in loci(1.5765、1.6214).Nei’s index of phenotypic diversity were 0.3523、0.3341,Shannon index 0.5148、0.4937 suggest the genetic differentiation in Zhenjiang is a litter higher than the Changing River’s offshore population.The numerical results are so approximate to each other that it is hard to identification.Although the two populations are spread a certain distance,the character of migration make the same water system’s population have a chance of gene communication.So the polarizations between the two populations are not so obviously.All these results shows that under the present natural environments eriocheir sinensis suffering fishing operation,pollution and other human factorshave become little influence that is to say they maintain the original genetic structures.This research using the AFLP technology to the Chinese East China Sea Anguilla japonica,the Changjiang River system eriocheir sinensis’ population genetic structure carries on the analysis for the first time,and appraises their present biological resources condition.So it is helpful to clearly understand the present stage of the above species living resources condition,and provide basis of solution for the management department.Extrapolating and grasping the speciesin and between populations’ genetic variation provide reference to the research of populations’ differentiation.更多还原