Phylogenetic analysis of coccidian parasites from invertebrates:: Search for missing links
Phylogenetic analysis of coccidian parasites from invertebrates:: Search for missing links
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DOI：
10.1016/j.protis.2006.02.005
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发表时间：
2006-06-01
期刊：
影响因子：
2.5
通讯作者：
Modry, David
中科院分区：
文献类型：
--
作者：
Kopecna, Jana;Jirku, Milan;Modry, David
顶复体寄生虫是最重要的单细胞真核寄生虫类群之一，包括重要的人类寄生虫，如疟原虫和刚地弓形虫。顶复合体的辐射以及它们对寄生生活方式的适应发生在脊椎动物时代之前。因此，无脊椎动物是顶复合体寄生虫的第一个宿主，这些寄生虫在后来的进化中转变为脊椎动物。尽管如此，迄今为止，在系统发育研究中，无脊椎动物的顶复合体寄生虫（除格林虫外）一直被忽视。为了解决这一问题，我们测序了头足类和甲壳类动物间传播的同种阿德琳娜（Adelina grylli）和阿德琳娜（Adelina dimidiata）的顶复体寄生虫，以及异种阿德琳娜（Aggregata octopiana）和阿德琳娜（Aggregata eberthii）的核SSU rRNA基因，并利用它们进行了系统发育重建。无论采用何种系统发育方法，adelinids作为Adeleorina亚目中Hepatozoon sp .的姊妹类群的地位都是稳定的。相比之下，Aggregata属的两个成员都具有高度不同的SSU rRNA基因，核苷酸组成不同寻常。正因为如此，它们形成了树中最长的分支，它们的位置是可变的。然而，在大多数分析中，Aggregata属与adelinids和hepatozoons一起分支，尽管它们在该聚类范围内的位置不稳定。(c) 2006 Elsevier GmbH版权所有。
Apicomplexan parasites represent one of the most important groups of parasitic unicellular eukaryotes comprising such important human parasites such as Plasmodium spp. and Toxoplasma gondii. Apicomplexan radiation as well as their adaptation to the parasitic style of life took place before the era of vertebrates. Thus, invertebrates were the first hosts of apicomplexan parasites that switched to vertebrates later in evolution. Despite this fact, apicomplexan parasites of invertebrates, with the exception of gregarines, have so far been ignored in phylogenetic studies. To address this issue, we sequenced the nuclear SSU rRNA genes from the homoxenous apicomplexan parasites of insects Adelina grylli and Adelina dimidiata, and the heteroxenous Aggregata octopiana and Aggregata eberthii that are transmitted between cephalopods and crustaceans, and used them for phylogenetic reconstructions. The position of the adelinids as a sister group to Hepatozoon spp. within the suborder Adeleorina was stable regardless of the phylogenetic method used. In contrast, both members of the genus Aggregata possess highly divergent SSU rRNA genes with an unusual nucleotide composition. Because of this, they form the longest branches in the tree and their position is variable. However, the genus Aggregata branches together with adelinids and hepatozoons in most of the analyses, although their position within the scope of this cluster is unstable. (c) 2006 Elsevier GmbH. All rights reserved.