Phylogenomics demonstrates that breviate flagellates are related to opisthokonts and apusomonads
Phylogenomics demonstrates that breviate flagellates are related to opisthokonts and apusomonads
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DOI：
10.1098/rspb.2013.1755
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发表时间：
2013-10-22
影响因子：
4.7
通讯作者：
Roger, Andrew J.
中科院分区：
文献类型：
--
作者：
Brown, Matthew W.;Sharpe, Susan C.;Roger, Andrew J.
大多数真核生物谱系属于少数几个主要群体之一。然而，一些原生生物谱系尚未被有力地放置在任何这些群体。短单胞菌和无单胞菌都是两个这样的谱系，它们似乎与变形虫和后孔动物（即“unikonts”或Amorphea）有关;然而，它们精确的系统发育位置仍然不清楚。在这里，我们描述了一个新的微需氧短形，Pygsuia biforma gen. nov. sp. nov.，分离自缺氧的河口沉积物。在超微结构上，这个物种类似于breviata和Subulatomonas，但有两个细胞形态，粘附和游泳。小亚单位rRNA基因的系统发育分析表明，Pygsuia是其他breviates的姐妹。我们构建了一个159个蛋白质的超矩阵，包括在Pygsuia的RNA-seq数据中鉴定的直系同源物。该数据集的系统基因组学分析表明，breviates，apusomonads和Opisthokonta形成一个强烈支持的主要真核生物类群，我们命名为Obazoa。虽然一些系统发育的方法不同意，证据的平衡表明，breviate血统形成最深的分支内Obazoa。我们还发现转录本编码一个几乎完整的整联蛋白粘附体从Pygsuia，这表明，这种蛋白质复合物参与后生动物多细胞性可能已经在真核生物进化比以前认为的更早。
Most eukaryotic lineages belong to one of a few major groups. However, several protistan lineages have not yet been robustly placed in any of these groups. Both the breviates and apusomonads are two such lineages that appear to be related to the Amoebozoa and Opisthokonta (i.e. the 'unikonts' or Amorphea); however, their precise phylogenetic positions remain unclear. Here, we describe a novel microaerophilic breviate, Pygsuia biforma gen. nov. sp. nov., isolated from a hypoxic estuarine sediment. Ultrastructurally, this species resembles the breviate genera Breviata and Subulatomonas but has two cell morphologies, adherent and swimming. Phylogenetic analyses of the small sub-unit rRNA gene show that Pygsuia is the sister to the other breviates. We constructed a 159-protein supermatrix, including orthologues identified in RNA-seq data from Pygsuia. Phylogenomic analyses of this dataset show that breviates, apusomonads and Opisthokonta form a strongly supported major eukaryotic grouping we name the Obazoa. Although some phylogenetic methods disagree, the balance of evidence suggests that the breviate lineage forms the deepest branch within Obazoa. We also found transcripts encoding a nearly complete integrin adhesome from Pygsuia, indicating that this protein complex involved in metazoan multicellularity may have evolved earlier in eukaryote evolution than previously thought.