Further analyses on the phylogeny of the subclass Scuticociliatia (Protozoa, Ciliophora) based on both nuclear and mitochondrial data
Further analyses on the phylogeny of the subclass Scuticociliatia (Protozoa, Ciliophora) based on both nuclear and mitochondrial data
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基于核和线粒体数据进一步分析盾纤毛亚纲（原生动物、纤毛纲）的系统发育
DOI：
10.1016/j.ympev.2019.106565
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发表时间：
2019
影响因子：
4.1
通讯作者：
Weibo Song
中科院分区：
文献类型：
--
作者：
Tengteng Zhang;Xinpeng Fan;Feng Gao;Saleh A.Al-Farraj;Hamed A.El-Serehy;Weibo Song
到目前为止，对纤毛原生生物的系统发育研究主要是基于单个位点，即核糖体DNA （rDNA）。为了避免单基因/基因组树的局限性，为系统分析提供更多的数据，线粒体DNA序列信息已越来越多地用于不同谱系的纤毛虫。在核基因的基础上，裸尾虫亚纲的系统关系是非常混乱的，很大程度上没有解决。在本研究中，我们从44个形态种的47个分离株中鉴定了72个新序列，包括40个线粒体细胞色素氧化酶c亚基I （COI）序列，29个线粒体小亚基核糖体DNA （mtSSU-rDNA）序列和3个核小亚基核糖体DNA （nSSU-rDNA）序列。结果表明：(1)与mtSSU-rDNA相比，COIgene与nsssu - rdna的系统发育关系更为一致；(2)预测并比较了扇尾虫mtSSU-rRNA V4区的二级结构，为近缘种的区分提供依据；(3)核和线粒体数据均不支持Loxocephalida目的单系性，这可能代表了scuticcoiliatia亚纲和Hymenostomatia亚纲之间的一些分化和中间谱系；(4)线粒体基因证实了thigmotricids归属于Pleuronematida目，混淆分类sulcigera comosaas归属于histiobalantiumia属；(5)核和线粒体资料显示，青霉口虫科的种属始终归属于胸膜菌属，表明青霉口虫更可能是由胸膜菌类祖先进化而来；(6)线粒体基因支持Philasterida目的单系性，但由于形态学和分子数据的差异，Philasterida目各科之间的关系仍存在争议。
So far, the phylogenetic studies on ciliated protists have mainly based on single locus, the nuclear ribosomal DNA (rDNA). In order to avoid the limitations of single gene/genome trees and to add more data to systematic analyses, information from mitochondrial DNA sequence has been increasingly used in different lineages of ciliates. The systematic relationships in the subclass Scuticociliatia are extremely confused and largely unresolved based on nuclear genes. In the present study, we have characterized 72 new sequences, including 40 mitochondrial cytochrome oxidase c subunit I (COI) sequences, 29 mitochondrial small subunit ribosomal DNA (mtSSU-rDNA) sequences and three nuclear small subunit ribosomal DNA (nSSU-rDNA) sequences from 47 isolates of 44 morphospecies. Phylogenetic analyses based on single gene as well as concatenated data were performed and revealed: (1) compared to mtSSU-rDNA,COIgene reveals more consistent relationships with those of nSSU-rDNA; (2) the secondary structures of mtSSU-rRNA V4 region are predicted and compared in scuticociliates, which can contribute to discrimination of closely related species; (3) neither nuclear nor mitochondrial data support the monophyly of the order Loxocephalida, which may represent some divergent and intermediate lineages between the subclass Scuticociliatia and Hymenostomatia; (4) the assignments of thigmotrichids to the order Pleuronematida and the confused taxonSulcigera comosato the genusHistiobalantiumare confirmed by mitochondrial genes; (5) both nuclear and mitochondrial data reveal that the species in the family Peniculistomatidae always group in the genusPleuronema, suggesting that peniculistomatids are more likely evolved fromPleuronema-like ancestors; (6) mitochondrial genes support the monophyly of the order Philasterida, but the relationships among families of the order Philasterida remain controversial due to the discrepancies between their morphological and molecular data.