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为了揭示游走类纤毛虫的系统发生,对寄生于淡水鱼类的车轮虫科中的6种车轮虫进行了18S rDNA的测序并获得了9个序列。采用了最大似然法(ML)与贝叶斯法(BI)对GenBank中所有游走类纤毛虫的18S rDNA序列进行了系统树的构建,并首次将SPSS与18S rDNA遗传距离结合分析了游走类纤毛虫的系统发生。研究结果进一步证实了车轮虫属(Trichodina)的非单系发生与小车轮虫属(Trichodinella)的有效性。此外,研究结合18S rDNA的GC含量与遗传距离分析提出了游走类纤毛虫科属及种间新的鉴定依据:18S rDNA的GC含量可用于游走类纤毛虫的科属区分,且与游走类纤毛虫的分化密切相关;18S rDNA的遗传距离在游走类纤毛虫的不同阶元中具有一定的阈值范围,即通常种内遗传距离阈值范围为0.000—4).005,属种间阈值范围为0.005—0.150,当遗传距离大于0.150时,则达到了科间水平。
To reveal the phylogeny of migratory ciliates, 18S rDNA sequences were sequenced and sequenced for 6 species of carps in the family Paleoepte parasitized in freshwater fishes. The 18S rDNA sequences of all migratory ciliates in GenBank were constructed by using maximum likelihood method (ML) and Bayesian method (BI). The genetic distance between SPSS and 18S rDNA was analyzed for the first time Systemic ciliates occur. The results further confirm the non-monogenic occurrence of Trichodina and the availability of Trichodinella. In addition, the study combined GC analysis of 18S rDNA and genetic distance analysis proposed a new identification of migratory ciliate families and species based on: GC content of 18S rDNA can be used for the taxonomic division of ciliates, and with the tour The genetic distance of 18S rDNA has a certain threshold range in different stages of migrating ciliates, that is, the intra-species genetic distance threshold is usually 0.000-4) .005, The threshold range of 0.005-0.150, when the genetic distance is greater than 0.150, then reached the inter-section level.