Phylogenetic analysis of the complete genome sequence of Encephalitozoon cuniculi supports the fungal origin of microsporidia and reveals a high frequency of fast-evolving genes
Phylogenetic analysis of the complete genome sequence of Encephalitozoon cuniculi supports the fungal origin of microsporidia and reveals a high frequency of fast-evolving genes
复制标题
DOI：
10.1007/s00239-004-2673-0
复制
发表时间：
2004-12-01
影响因子：
3.9
通讯作者：
Gouy, M
中科院分区：
文献类型：
--
作者：
Thomarat, F;Vivarès, CP;Gouy, M
微孢子虫是单细胞真核生物，是专性细胞内寄生虫。由于缺乏线粒体，它们最初被认为在线粒体起源的内共生之前已经分化。微孢子虫最初是线粒体的，这一观点首先受到与线粒体蛋白同源基因的发现的质疑，然后被细胞质中线粒体残留物的鉴定所驳斥。不同的分子系统发育也对微孢子虫的早期分化产生了怀疑，这些有机体与真菌或真菌内部形成一个单系群。2001个被认为是由脑囊虫全基因组编码的蛋白质为验证这一假设提供了有力的数据。对99个被选为系统发育标记的蛋白的系统发育分析表明，具有最低进化率的线虫序列优先与真菌序列聚集在一起，或者更罕见地与动物和真菌序列聚集在一起。由于进化率低的序列对长枝吸引伪影的敏感性较低，我们得出结论，微孢子虫与真菌在进化上有亲缘关系。该分析还允许将几种系统发育算法的准确性与真实序列而不是模拟序列进行快速进化谱系的比较。
Microsporidia are unicellular eukaryotes living as obligate intracellular parasites. Lacking mitochondria, they were initially considered as having diverged before the endosymbiosis at the origin of mitochondria. That microsporidia were primitively amitochondriate was first questioned by the discovery of microsporidial sequences homologous to genes encoding mitochondrial proteins and then refuted by the identification of remnants of mitochondria in their cytoplasm. Various molecular phylogenies also cast doubt on the early divergence of microsporidia, these organisms forming a monophyletic group with or within the fungi. The 2001 proteins putatively encoded by the complete genome of Encephalitozoon cuniculi provided powerful data to test this hypothesis. Phylogenetic analysis of 99 proteins selected as adequate phylogenetic markers indicated that the E. cuniculi sequences having the lowest evolutionary rates preferentially clustered with fungal sequences or, more rarely, with both animal and fungal sequences. Because sequences with low evolutionary rates are less sensitive to the long-branch attraction artifact, we concluded that microsporidia are evolutionarily related to fungi. This analysis also allowed comparing the accuracy of several phylogenetic algorithms for a fast-evolving lineage with real rather than simulated sequences.