Multiple origins of Heliozoa from flagellate ancestors: New cryptist subphylum Corbihelia, superclass Corbistoma, and monophyly of Haptista, Cryptista, Hacrobia and Chromista
Multiple origins of Heliozoa from flagellate ancestors: New cryptist subphylum Corbihelia, superclass Corbistoma, and monophyly of Haptista, Cryptista, Hacrobia and Chromista
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DOI：
10.1016/j.ympev.2015.07.004
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发表时间：
2015-12-01
影响因子：
4.1
通讯作者：
Lewis, Rhodri
中科院分区：
文献类型：
--
作者：
Cavalier-Smith, Thomas;Chao, Ema E.;Lewis, Rhodri
日光虫原生生物具有辐射状细胞突起（轴足），由中心体成核的微管轴丝支撑，并带有用于捕捉猎物的颗粒状挤出体。为了澄清先前令人困惑的日光虫系统发育，我们对两种微小的裸日光虫（内海微日虫和中心海藻 Oxnerella marina）以及尾虫类伪日光虫 Minimassisteria diva 的部分转录组进行了测序。对 187 个基因的系统发育分析证实，所有基因都是染色者；但中心螺旋（排列成六边形和三角形的微管）与在跨核细胞质通道（三角形或方形微管阵列）中具有轴丝的内壁细胞不是姐妹。 Centrohelids 与 haptophytes 是紧密的姐妹（统称为 Haptista 门）；我们解释了它们的轴足和触线体的共同起源。 Micro heliella 是新超纲 Corbistoma（动物鞭毛纲 Telonemea 和 Picomonaadea，具有不对称微丝状咽篮）的姐妹，表明这些轴足原生生物是独立于动物祖先进化而来的。我们将 Corbistoma 和 Endohelea 归类为新的隐秘亚门 Corbihelia，具有致密的纤维状细胞间连接；内腱轴突和端粒皮质在超微结构上是相关的。不同样本的树木阐明了为什么皮质多基因真核生物系统发育是有问题的：长分支人工制品可能扭曲了皮质动物的深层多基因系统发育（Plantae，Chromista）；由于基础辐射的极端接近性和贝叶斯星树悖论，基础辐射可能会被矛盾地重建。 Haptista 和 Hacrobia 是全系的，而 Chromista 可能是全系的。 (C) 2015 年作者。由爱思唯尔公司出版
Heliozoan protists have radiating cell projections (axopodia) supported by microtubular axonemes nucleated by the centrosome and bearing granule-like extrusomes for catching prey. To clarify previously confused heliozoan phylogeny we sequenced partial transcriptomes of two tiny naked heliozoa, the endohelean Microheliella maris and centrohelid Oxnerella marina, and the cercozoan pseudoheliozoan Minimassisteria diva. Phylogenetic analysis of 187 genes confirms that all are chromists; but centrohelids (microtubules arranged as hexagons and triangles) are not sisters to Endohelea having axonemes in transnuclear cytoplasmic channels (triangular or square microtubular arrays). Centrohelids are strongly sister to haptophytes (together phylum Haptista); we explain the common origins of their axopodia and haptonema. Micro heliella is sister to new superclass Corbistoma (zooflagellate Telonemea and Picomonadea, with asymmetric microfilamentous pharyngeal basket), showing that these axopodial protists evolved independently from zooflagellate ancestors. We group Corbistoma and Endohelea as new cryptist subphylum Corbihelia with dense fibrillar interorganellar connections; endohelean axopodia and Telonema cortex are ultrastructurally related. Differently sampled trees clarify why corticate multigene eukaryote phylogeny is problematic: long-branch artefacts probably distort deep multigene phylogeny of corticates (Plantae, Chromista); basal radiations may be contradictorily reconstructed because of their extreme closeness and the Bayesian star-tree paradox. Haptista and Hacrobia are holophyletic, and Chromista probably are. (C) 2015 The Authors. Published by Elsevier Inc.