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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.

为了估计顶质体（一种通常存在于大多数顶复合体寄生虫中的质体样细胞器）的起源和进化，并进一步了解顶复合体门的系统发育关系，我们克隆并测序了来自不同分类谱系的编码核糖体rna、延伸因子、异质和谷氨酸trna合成酶的基因。其中包括顶孢子虫（疟原虫、弓形虫、巴贝虫、隐孢子虫）、层孢子虫（囊虫、原孢子虫）、裸孢子虫（飞虫）、阿米巴虫（内阿米巴虫、虫形虫）和微孢子虫（Glugea、脑孢子虫）。利用这些数据结合公共数据库中的相关序列，采用分子系统发育的最大似然方法对每个基因进行了详细的系统发育分析。从单个基因的分析得出的估计对数似然进行了总结，并在最大似然方法的框架下进行了组合系统发育。在此基础上，迄今为止获得了以下系统发育发现：(1)隐孢子虫属是顶复亚目最早的分支；(2)在疟原虫属（Piasmodiuni）中尚不清楚其系统发育位置的coatneyi疟原虫与间日疟原虫和其他类人猿寄生虫接近；(3)尖复合体门的近亲是尖鞭毛虫，纤毛虫属与尖复合体门和尖鞭毛虫的共同祖先有姐妹类群的地位；(4)高阶谱系Alveolata的单系性，包括顶复合体、双鞭毛虫和纤毛虫，由多个基因支持；(5)Alveolata与其他高阶谱系——层桩相近；(6)肺泡门和链孔门的共同祖先接近真核生物树中的真核动物门或绿枝植物门。