碘泡虫属粘孢子虫分子进化及其与宿主协同关系的研究
Molecular Evolution of Myxobolus (Myxosporea) and Coevolution with their Hosts

中文摘要：以18S rDNA为分子标记,对碘泡虫属 Myxobolus粘孢子虫的分子进化规律进行了系统研究。结果显示:碘泡虫属各物种18S rDNA的AT含量(53.2%)高于GC含量(46.8%),表现出一定的AT组成偏向性;各物种18S rDNA遗传距离在0.00~0.35;脑碘泡虫 M. cerebralis保守区序列变异介于淡水物种和广盐性物种之间;碘泡虫属18S rDNA分子系统发育树呈现生境相同先聚枝,形态相似后聚枝的规律,并表现出一定的宿主特异性和组织向性。此外,以线粒体COⅠ基因为分子标记,对碘泡虫属相应宿主进行了系统进化分析,结果表明:淡水物种与广盐性物种分别聚在不同的分类枝系中,与寄生于宿主体内的碘泡虫所呈现的支序树有相同的进化趋势,并表现出一定的协同进化关系;海水起源的虹鳟 Oncorhynchus mykiss在适应淡水过程中被脑碘泡虫寄生,两者经过长期的演化,最终适应淡水环境。
英文摘要：18S rDNA as a molecular marker was used to explore the rule of molecular evolution in Myxobolus myxosporeans. The results indicated that, among each species in Myxobolus, the AT contents (53.2%) of 18S rDNA were higher than GC contents (46.8%), and therefore showed a somewhat AT bias; the genetic distances of 18S rDNA among each species was ranged from 0.00 to 0.35; within the conserved regions of 18S rDNA, the variation level in M. cerebralis was between that of freshwater and euryhaline species; phylogenetic trees based on 18S rDNA showed that species with the same habitats tend to cluster together firstly, and then the sublines could be clustered according to the morphological similarity of spores. Moreover, the clustering tendency indicated some degree of host and tissue specificity. Phylogenetic analyses on the hosts of Myxobolus based on COⅠ gene showed that the freshwater and euryhaline species were grouped into different lineages, revealing the same evolution trend of Myxobolus, and presenting the coevolution relationships of hosts-parasites; M. cerebralis might be the myxosporean who parasited on marine origined fish Oncorhynchus mykiss in the process of adapting to the freshwater environment. 2016,(35): 183-189 收稿日期：2015-10-16 DOI：10.11984/j.issn.1000-7083.20150322 分类号：Q959.115 基金项目：国家自然科学基金项目(No.31471980; No.31501845); 重庆市科委基金项目(No.cstc2010ca1010; No.cstc2014jcyjA80014); 重庆市教委科技项目(KJ1400502) 作者简介：陈围(1988-), 女, 硕士研究生, 研究方向为鱼类寄生虫学, E-mail:weer2013@foxmail.com *通讯作者：杨承忠, E-mail:drczyang@126.com;赵元莙, zhaoyuanjuncqnu@126.com 参考文献： 董江丽, 赵元莙, 唐发辉, 等. 2011. 黄颡单尾虫(粘体门,双壳目)的重描述及基于28S rDNA和ITS-5.8S序列的系统地位分析[J]. 动物分类学报, 36(1): 84-92. 刘澧津. 1996. 虹鳟[J]. 水产学杂志, 9(1): 73-75. 索栋, 赵元莙. 2010. 尼氏单极虫(粘体门, 双壳目)的重描述及基于18S rDNA的系统地位分析[J]. 动物分类学报, 35(1): 90-95. Andree KB, EL-Matbouli M, Hoffman RW, et al . 1999. Comparison of 18S and ITS-1 rDNA sequences of selected geographic isolates of Myxobolus cerebralis [J]. International Journal for Parasitology, 29(5): 771-775. Brooks DR, McLennan DA. 1991. Parascript: parasites and the language of evolution[M]. Washington: Smithsonian Institution Press: 57-69. Brooks DR. 1981. Hennig's parasitological method: a