The twilight of Heliozoa and rise of Rhizaria, an emerging supergroup of amoeboid eukaryotes
The twilight of Heliozoa and rise of Rhizaria, an emerging supergroup of amoeboid eukaryotes
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DOI：
10.1073/pnas.0308602101
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发表时间：
2004-05-25
影响因子：
11.1
通讯作者：
Pawlowski, J
中科院分区：
文献类型：
--
作者：
Nikolaev, SI;Berney, C;Pawlowski, J
最近的分子系统发育研究揭示了单细胞真核生物的非凡多样性。然而，由于缺乏一些易于识别和可培养的主要原生生物的分子数据，对这种多样性的适当评估和真核生物系统发育的准确重建仍然受到阻碍。其中，变形虫类真核生物尽管具有多样性、复杂性和丰富性，但在分子系统学中却明显缺失。为了部分填补这一系统发育的空白，我们在这里提供了“Heliozoa”的三个主要类群(放线纲、中心纲和桥胸纲)、类Heliozoa的Sticholonche和放射虫的Polycystina组的小亚基核糖体RNA和肌动蛋白序列数据。对我们的序列的系统发育分析表明，日光动物是多种多样的，它要么作为一个独立的真核世系(Centrohelida)分支，要么作为一个独立的真核血统(Centrohelida)分支，要么在稻草纲(Actinophryida)内分支，要么在尾丝虫(Desmoatriida)之间分支，这与之前的基于超微结构的研究大体一致。我们的数据也为根状线虫的存在提供了确凿的证据，根状线虫是一个新兴的超类群，主要是变形虫类真核生物，包括桥粒藻类、所有放射虫、有孔虫和有孔虫，以及各种纤毛虫和网状阿米巴虫和一些鞭毛虫。
Recent molecular phylogenetic studies revealed the extraordinary diversity of single-celled eukaryotes. However, the proper assessment of this diversity and accurate reconstruction of the eukaryote phylogeny are still impeded by the lack of molecular data for some major groups of easily identifiable and cultivable protists. Among them, amoeboid eukaryotes have been notably absent from molecular phylogenies, despite their diversity, complexity, and abundance. To partly fill this phylogenetic gap, we present here combined small-subunit ribosomal RNA and actin sequence data for the three main groups of "Heliozoa" (Actinophryida, Centrohelida, and Desmothoracida), the heliozoan-like Sticholonche, and the radiolarian group Polycystinea. Phylogenetic analyses of our sequences demonstrate the polyphyly of heliozoans, which branch either as an independent eukaryotic lineage (Centrohelida), within stramenopiles (Actinophryida), or among cercozoans (Desmothoracida), in broad agreement with previous ultrastructure-based studies. Our data also provide solid evidence for the existence of the Rhizaria, an emerging supergroup of mainly amoeboid eukaryotes that includes desmothoracid heliozoans, all radiolarians, Sticholonche, and foraminiferans, as well as various filose and reticulose amoebae and some flagellates.