Multigene-based phylogeny analyses of the controversial family Condylostomatidae (Ciliophora, Heterotrichea)
Multigene-based phylogeny analyses of the controversial family Condylostomatidae (Ciliophora, Heterotrichea)
复制标题
对有争议的Condylostomatidae科（纤毛目、异毛目）进行基于多基因的系统发育分析
DOI：
10.1111/zsc.12383
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发表时间：
2019-09-24
影响因子：
2.5
通讯作者：
Xu, Kuidong
中科院分区：
文献类型：
--
作者：
Chen, Xumiao;Li, Ju;Xu, Kuidong
Condylostoma是Condylostomatidae科的模式属，是一个著名的和分类学上混乱的属，有30多个命名种。尽管在过去的几十年里不断发现新的物种和详细的重新描述已知的物种之间的同源物和相关属的系统发育关系仍然模糊。基于从9个Condylostoma分离株中获得的24个新序列，我们结合多个标记基因进行了系统发育分析。分子系统发育树表明：（1）Condylostomatidae的单系性得到了rDNA位点和SSU rDNA序列的支持，支持值较高，但ITS 1 -5. 8 S-ITS 2和LSU rDNA序列不再支持;（B）Condylostoma很可能是一个并系属，不能否认它是一个多系群的可能性，（3）Condylostentor属和Chattonidium属可能是由Condylostoma属的辐射群演化而来。此外，为了更好地理解髁口虫的进化关系，预测了SSU rDNA和ITS 2转录本的可变区2和4（V2和V4）的二级结构。结果表明，V2和V4结构在属的水平上是相当保守的，而ITS 2结构的变异要大得多。
Condylostoma, the type genus of the family Condylostomatidae, is a well-known and taxonomically confusing genus with more than 30 nominal species. The phylogenetic relationships among congeners and related genera remain obscure despite the continuous discovery of new species and detailed redescription of known species over the past decades. Based on a total of 24 new sequences obtained from nine Condylostoma isolates, we conducted phylogenetic analyses by combining multiple marker genes. The molecular phylogenetic trees indicate that: (a) the monophyly of the family Condylostomatidae is supported by the rDNA locus and SSU rDNA sequences with high support value but is no longer sustained by both the ITS1-5.8S-ITS2 and LSU rDNA sequences; (b) Condylostoma is very likely a paraphyletic genus, and the possibility that it is a polyphyletic group cannot be denied, and (c) the genera Condylostentor and Chattonidium are suggested to evolve from a radiation of Condylostoma species. Furthermore, in an effort to provide better resolutions for understanding the evolutionary relationships of condylostomatids, the secondary structures of the variable regions 2 and 4 (V2 and V4) of SSU rDNA and ITS2 transcripts are predicted. The results revealed that the V2 and V4 structures are rather conserved at the genus level, while the ITS2 structures are much more variable.