Phylogeny of primary photosynthetic eukaryotes as deduced from slowly evolving nuclear genes
Phylogeny of primary photosynthetic eukaryotes as deduced from slowly evolving nuclear genes
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DOI：
10.1093/molbev/msm091
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发表时间：
2007-08-01
影响因子：
10.7
通讯作者：
Watanabe, Masakatsu
中科院分区：
文献类型：
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作者：
Nozaki, Hisayoshi;Iseki, Mineo;Watanabe, Masakatsu
光合作用真核生物的生物多样性，传统上被认为是9个藻纲或门，归因于两种涉及质体的内生共生事件：初级内生共生和次生内生共生。因此，初级光合作用真核生物的系统发育地位是理解真核细胞进化和建立高等分类概念的基础。最近，RodrıGuez-Ezpeleta等人(2005年)证明了三类主要的光合作用真核生物(绿色植物、蓝藻和红藻)在143个核基因的基础上具有很强的单一性。然而，他们只分析了属于Stramenopiles-Alveolata(SA)谱系的次级光养生物的两个部分，他们的143个基因包括快速进化的基因。在这里，我们基于主要从RodrıGuez-Ezpeleta等人(2005年)的数据矩阵中选择的缓慢进化的核基因，使用不属于SA谱系的自由生活的次生光营养类群(Haptophyta)和Excavata(异叶藻纲和Reclinomonas)的额外可操作分类单元(OTU)，重新审视初级光养生物的系统发育。我们的系统发育结果证明了原生光养生物的强烈非单系性和红藻在双孔藻中的基本位置，这表明在单个叶绿体初级内共生的假设下，某些真核生物谱系中的叶绿体丢失了。
The biodiversity of photosynthetic eukaryotes, traditionally recognized as nine algal divisions or phyla, is attributed to two kinds of endosymbiotic events involving plastids: primary endosymbiosis and secondary endosymbiosis. Therefore, the phylogenetic positions of primary photosynthetic eukaryotes are fundamental for understanding the evolution of eukaryotic cells and establishing higher taxonomic concepts of eukaryotes. Recently, Rodrıguez-Ezpeleta et al.(2005) demonstrated the strong monophyly of the three groups of primary photosynthetic eukaryotes (green plants, glaucophytes, and red algae) based on 143 nuclear genes. However, they analyzed only two divisions of the secondary phototrophs belonging to the Stramenopiles–Alveolata (SA) lineage, and their 143 genes included rapidly evolving genes. Here, we reexamine the phylogeny of the primary phototrophs based on slowly evolving nuclear genes selected mainly from the data matrix of Rodrıguez-Ezpeleta et al.(2005), using additional operational taxonomic units (OTUs) of a free-living, secondary phototrophic group (Haptophyta) and of Excavata (Heterolobosea and Reclinomonas) that do not belong to the SA lineage. Our phylogenetic results demonstrate the robust non-monophyly of the primary phototrophs and the basal position of red algae within the bikonts, suggesting the loss of plastids in certain eukaryotic lineages under the assumption of the single plastid primary endosymbiosis.