Du Yan-Hong, Zhao Yuan-Jun, Tang Fa-Hui
Chongqing Key Laboratory of Animal Biology, Chongqing Normal University, Chongqing, 401331, People's Republic of China.
Curr Microbiol. 2018 Mar;75(3):296-304. doi: 10.1007/s00284-017-1379-7. Epub 2017 Oct 26.
We analyzed the secondary structure of the small subunit (SSU) rRNA genes of Mobilida (Ciliophora, Peritrichia) and found that the secondary structures of some regions within the SSU-rRNA gene are distinct between the families Trichodinidae and Urceolariidae. Therefore, some of these important regions including H10, H11, H17, H47, H29, H30, H37, E10-1, H45-H46, and V4 (E23-4, E23-7) could be used as the barcodes for classification of these two families. In contrast, V4 (E23-1, E23-2) belongs to a hypervariable region and is not a good barcode at the genus level because of its great inter-specific variation. Our results indicated that the comprehensive analysis of the secondary structure of SSU-rRNA genes is a reliable auxiliary approach for phylogenic study of mobilid ciliates. It was further found that the coevolution between hosts or habitats and the Mobilida ciliates was existent, because the host types and their habitats were critical ecological factors that influenced the evolution of Mobilida ciliates.
我们分析了游动目（纤毛虫纲，缘毛亚纲）小亚基（SSU）rRNA基因的二级结构，发现毛盘虫科和壶形虫科的SSU-rRNA基因内某些区域的二级结构有所不同。因此，这些重要区域中的一些，包括H10、H11、H17、H47、H29、H30、H37、E10-1、H45-H46和V4（E23-4、E23-7），可作为这两个科分类的条形码。相比之下，V4（E23-1、E23-2）属于一个高变区，由于其种间差异很大，在属水平上不是一个好的条形码。我们的结果表明，对SSU-rRNA基因二级结构的综合分析是游动目纤毛虫系统发育研究的可靠辅助方法。进一步发现，宿主或栖息地与游动目纤毛虫之间存在协同进化，因为宿主类型及其栖息地是影响游动目纤毛虫进化的关键生态因素。
