利用线粒体DNA控制区序列分析细鳞鲑种群的遗传结构  

DNA sequence variation in the mitochondrial control region of lenok (Brachymystax lenok) populations in China

作　　者：夏颖哲[1] 盛岩[1] 陈宜瑜[2] 

机构地区：[1]中国科学院动物研究所,北京100080 [2]中国科学院,北京100864

出　　处：《生物多样性》2006年第1期48-54,共7页Biodiversity Science

基　　金：国家基础科学人才培养基金(NSFC-J0030092);中国科学院院长基金(A2901046)

摘　　要：细鳞鲑(Brachymystaxlenok)是我国重要的经济鱼类,由于过度捕捞、环境污染及其他因素的影响,其种群已处于濒危状态。研究细鳞鲑种群的遗传结构对于探讨这一物种的形成与演化及其有效保护等问题具有十分重要的意义。本文测定了我国东部水系的细鳞鲑7个种群71个个体的线粒体DNA控制区序列片段(835bp),发现43个变异位点,共计15个单倍型。AMOVA分析结果表明,不同的地理区域之间存在显著的遗传分化(63.55%),而区域内和种群内的遗传变异分别只有24.17%和12.28%。采用邻接法(NJ)构建分子系统树,结果表明,单倍型被分成3个与各自的地理区域相对应的族群,各地理区域之间没有共享的单倍型。细鳞鲑的这种独特的遗传结构与其进化历史(例如地理隔离造成基因流的长期中断)和生物学特性(例如有限的散布能力和基因交换能力)有密切的关系。根据上述研究结果,我们建议对这3个遗传分化显著的地理区域加以保护,并按照不同的水系来保护种群,避免不同区域的种群之间发生基因交流。Brachymystax lenok （Salmonidae） is an economically important fish species in China whose population is currently declining due to overexploitation and environmental pollution. Recently it has been listed as a threatened species in the China Red Data Book of Endangered Animals. To study the genetic structure and phylogeographic pattern of its populations is important for addressing the systematics, evolution, and effective conservation of this species. Partial sequences of the mitochondrial control region （835 bp） were obtained by PCR amplification of 71 individuals of Brachymystax lenok from seven populations in China＇s eastern river systems. A total of 43 （5.1%） nucleotides were variable, resulting in a total of 15 haplotypes. Analysis of molecular variance indicated that a high proportion of the total genetic variance was attributable to variations among regions （63.55%）, whereas 24.17% and 12.28% occurred among populations within regions and within populations, respectively. A molecular phylogenetic tree constructed using the neighbor-joining （NJ） method suggested that the 15 haplotypes were assigned to three clades associated with geographic regions. There were no shared haplotypes found among regions. The pattern of phylogenetic discontinuity, which is associated with spatial separation, is a result of both historical （long-term, zoogeographic barriers to gene flow） and contemporary （limited dispersal and gene flow capabilities） factors. Based on these results, we propose that each of the three evolutionafily distinct groups of lenok populations should be protected from loss of biodiversity. It is highly recommended that management efforts should be focused on riverine conservation, avoiding translocations from the populations of different regions.

关 键 词：遗传变异 单倍型 基因流 Brachymystax lenok 

分 类 号：S917.4[农业科学—水产科学]