Arisue Nobuko, Hashimot Tetsuo, Lee Jennifer A, Moore Dorothy V, Gordon Paul, Sensen Christoph W, Gaasterland Terry, Hasegawa Masami, Müller Miklós
Department of Biosystems Science, Graduate University for Advanced Studies (Sokendai), Hayama, Kanagawa, Japan.
J Eukaryot Microbiol. 2002 Jan-Feb;49(1):1-10. doi: 10.1111/j.1550-7408.2002.tb00332.x.
The taxonomic position and phylogenetic relationships of the Pelobionta, an amitochondriate amoeboflagellate group, are not yet completely settled. To provide more information, we obtained sequences for the large subunit rDNA gene, the gene for translation elongation factor 1alpha, and for a large part of the gene encoding translation elongation factor 2 from a representative of this group, Mastigamoeba balamuthi (formerly Phreatamoeba balamuthi). The gene for the large subunit rDNA was unusually large compared to those of other protists, a phenomenon that had previously been observed for the gene encoding the small subunit rDNA. Phylogenetic reconstruction using a maximum likelihood method was performed with these sequences, as well as the gene encoding the small subunit rDNA. When evaluated individually, the M. balamuthi genes for the small and large subunit rDNAs and elongation factor 1alpha had a most recent common ancestor with either the Mycetozoa (slime molds) or with Entamoeba histolytica. A clade formed by M. balamuthi, E. histolytica, and Mycetozoa was not rejected statistically for any of the sequences. A combined maximum likelihood analysis using 3,935 positions from all molecules suggested that these three taxonomic units form a robust clade. We were unable to resolve the closest group to this clade using the combined analysis. These findings support the notion, which had previously been proposed primarily on cytological evidence, that both M. balamuthi and E. histolytica are closely related to the Mycetozoa and that these three together represent a major eukaryotic lineage.
无线粒体阿米巴鞭毛虫类群Pelobionta的分类地位和系统发育关系尚未完全确定。为了提供更多信息，我们从该类群的一个代表——巴氏鞭毛虫（以前称为嗜热变形虫）中获得了大亚基rDNA基因、翻译延伸因子1α基因以及编码翻译延伸因子2的大部分基因的序列。与其他原生生物的大亚基rDNA基因相比，该基因异常大，这一现象先前在编码小亚基rDNA的基因中也有观察到。使用最大似然法对这些序列以及编码小亚基rDNA的基因进行了系统发育重建。单独评估时，巴氏鞭毛虫的小亚基和大亚基rDNA基因以及延伸因子1α与黏菌（黏菌门）或溶组织内阿米巴有最近的共同祖先。对于任何序列，由巴氏鞭毛虫、溶组织内阿米巴和黏菌门形成的一个分支在统计学上都未被否定。使用来自所有分子的3935个位置进行的联合最大似然分析表明，这三个分类单元形成了一个稳健的分支。我们无法通过联合分析确定与该分支最接近的类群。这些发现支持了先前主要基于细胞学证据提出的观点，即巴氏鞭毛虫和溶组织内阿米巴都与黏菌门密切相关，并且这三者共同代表了一个主要的真核生物谱系。
