下毛目分子系统进化研究和鬃棘尾虫再描述(纤毛动物门:下毛目:尖毛虫科)

MOLECULAR PHYLOGENETIC ANALYSIS OF ORDER HYPOTRICHIDA WITH REDESCRIPTION OF STYLONYCHIA PUSTULATA (CILIOPHORA:HYPOTRICHIDA:OXYTRICHIDAE)

作者自武汉东湖采集的样本中分离出鬃棘尾虫Stylonychiapustulata ,利用活体观察与蛋白银染色技术进行了形态学研究 ,并测定了核糖体小亚基RNA基因全序列 ;以邻接法 (Neighbor Joining ,NJ)和最大简约性法 (MaximumParsimonyMethod ,MP)对该物种与GenBank中所有其它下毛目物种进行了分子系统发育分析。结果显示 :所研究下毛目种类皆聚为一支 ,支持下毛目为单系观点 ;尖毛虫属和棘尾虫属物种聚类相互交错 ,因此结合形态学上分类标志的分析 ,对这两个属存在的合理性提出异议。根据本文对同种不同种群的小腔游仆虫Euplotesaedicalatus、尖毛虫Oxytrichagranulifera以及鬃棘尾虫Stylonychiapustulata分子进化分析 。

The hypotrichous ciliate Stylonychia pustulata was collected from Donghu Lake in Wuhan, China and clonal culture was eastablished. The morphological characters of this organism were observedin vivo and using protargol impregnated specimens. By determining the small subunit ribosome RNA gene seqence and combing with the sequences of other hypotrichous from GenBank, we constructed two molecular phylogenetic trees using both Neighbor-joining and Maximum parsimony methods. According to the tees and morphology characters, three conclusions have been deduced: 1) hypotrichous belong to a monophylic group; 2) associated with morphology research, two topologies both indicate that species of Stylonychia can not be parted from Oxytricha, this disagrees with the traditional taxonomic system; 3) from the analysis of different groups of Euplotes aediculatus, Oxytricha granulifera and Stylonychia pustulata, in author′s opinion, it is important that we combine morphology and molecular characters to a type species for further taxonomic and phylogenetic research.