Origin and evolution of plastid-like organella in Apicomplexa

顶端复合体类质体细胞器的起源和进化

基本信息

批准号：
13640709
负责人：
HASEGAWA Masami
金额：
$ 2.18万
依托单位：
The Institute of Statistical Mathematics
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2001
资助国家：
日本
起止时间：
2001 至 2002
项目状态：
已结题

项目摘要

In order to estimate origin and evolution of the apicoplast, a plastid-like organelle that is usually found in most of apicomplexan parasites, and to gain more insights into the phylogenetic relationships concerning the phylum Apicomplexa, we cloned and sequenced genes encoding ribosomal RNAs, elongation factors, isoleucyl-and valyl-tRNA synthetases from diverse taxonomic lineages. These include Apicomplexa (Plasmodium, Toxoplasma, Babesia, Cryptosporidiuni), stramenopiles (Blastocystis, Proterornonas), Euglenozoa (Thypanosoma), Amoebozoa (Entamoeba, Mastigamoeba), and Microsporidia (Glugea, Encephalitozoon). Using these data in combination with related sequences in the public databases, detailed phylogenetic analyses were carried out on each of the individual genes by the maximum likelihood method of molecular phylogeny. The estimated log-likelihoods derived from the analyses of individual genes were summed up and combined phylogeny was performed in a framework of the maximum likelihood approach. Based on these analyses the following phylogenetic findings have been obtained up to now: (1)The genus Cryptosporidiurn is the earliest offshoot of Apicomplexa; (2) Plasmodium coatneyi, the phylogenetic position of which had been unknown in the genus Piasmodiuni (malaria 'parasites), is close to P vivax and other simian parasites;(3)The closest relative of the phylum Apicomplexa is dianofiagellates, and the genus Ciliophora shares a sister group' position to the common ancestor of Apicomplexa and dianoflagellates; (4)Monophyly of the higher-order lineage, Alveolata, including Apicomplexa, dianofiagellates, and Ciliophora is supported by several genes; (5)Alveolata is close to the other higher-order lineage, stramenopiles; (6)The common ancestor of Alveolata and strarnenopiles is close to Euglenozoa or to Viiridiplantae in the tree of Eukaryota.

为了估计顶复门（大多数顶复门寄生虫中常见的质体样细胞器）的起源和进化，并为了更深入地了解顶复门的系统发育关系，我们克隆并测序了编码核糖体RNA、伸长率的基因。来自不同分类谱系的因子、异亮酰-和缬氨酰-tRNA 合成酶。这些包括顶复菌门（疟原虫、弓形虫、巴贝虫、隐孢子虫）、原生藻菌（囊胚、原胞菌）、眼虫（胸囊虫）、变形虫（内阿米巴、马斯蒂加阿米巴）和微孢子虫（胶体、脑炎虫）。将这些数据与公共数据库中的相关序列相结合，通过分子系统发育的最大似然法对每个单独的基因进行详细的系统发育分析。总结了从单个基因分析中得出的估计对数似然，并在最大似然方法的框架中进行了组合系统发育。基于这些分析，目前已获得以下系统发育发现：（1）隐孢子虫属是顶复门最早的分支； (2) 科特尼疟原虫 (Plasmodiumcoatneyi)，其在 Piasmodiuni 属中的系统发育位置未知，与间日疟原虫和其他猿类寄生虫接近；(3) 顶复门 (Apicomplexa) 的近亲是双鞭毛虫 (dianofiagellates) 属，纤毛纲与顶复纲和鞭毛纲的共同祖先处于姐妹群地位； (4)高阶谱系Alveolata的单系性，包括Apicomplexa、dianofiagellates和Ciliophora由多个基因支持； (5)Alveolata与另一个高级谱系原生藻菌接近； (6)藻类和原生菌的共同祖先与真核生物树中的眼虫纲或Viiridiplantae接近。