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Testing the Chromist monophyly based on multi-gene phylogenetic analyses considering the sequence data from katablepharids.

考虑来自 katablepharids 的序列数据，基于多基因系统发育分析测试 Chromist 单系性。

基本信息

批准号：
18570214
负责人：
INAGAKI Yuji
金额：
$ 2.5万
依托单位：
University of Tsukuba
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2006
资助国家：
日本
起止时间：
2006 至 2007
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-18570214/
关键词：
Molecular evolution Eukaryotic phylogeny Combined phylogenetic analysis Chromist hypothesis Plastids 分子進化

项目摘要

The Chromist hypothesis assumes the host lineages of stramenopiles, cryptomonads, and haptophytes are monophyletic, and a common ancestor of the three "chromist" groups had captured plastids containing chlorophyll a plus c through an endosymbiosis of a red alga. So far, molecular phylogenetic analyses based on nucleus-encoded genes have not recovered the Chromist monophyly as a whole, except a robust sister relationship between cryptomonad and haptophyte host lineages.A small taxonomic group of heterotrophic unicellular eukaryotes (protists), katablepharids, has been considered as an evolutionary relatives of cryptomonads, whereas the sequence data of this protist lineage has not much accumulated to date. We currently purchased two culture strains of katablepharids, such as Leucocyrptos marina and Katablepharids japonica, and are culturing these cells in our laboratory to determine marker genes for phylogeny from the two katablepharids. In the initial research project, we planned to ma … More ke a cDNA library for these cells, and conduct expressed sequence tags (EST) sequencing on the libraries. Unfortunately, no library is available so far, since it is difficult to eliminate the nucleic acid sample of prey (haptophyte) cells from the cDNA extracted from katablepharids cells. However, we successfully isolated translation elongation factor 2 (EF2) and elongation factor-like genes from L. marina. Interestingly, the robust, clade of haptophytes, cryptomonads, and katablepharids was reconstructed in a preliminary EF2 phylogeny, and this clade further showed affinity to ted algae and green plants. This tree topology obtained from the EF2 analysis suggests that haptophytes, cryptomonads, and katablepharids indeed share a common ancestry to the exclusion of other eukaryotes, and the EF2 gene was laterally transferred from a lineage belong to the Plantae to the ancestral cells of haptophytes, cryptomonads, and katablepharids. On the other hand, phylogenetic of EFL genes reject the monophyly of haptophytes, cryptomonads, and katablepharids, indicating that the three lineages independently acquired EFL genes from three distinctive sources. Less

染色质假说假设层枝藻、隐藻和附着藻的宿主谱系是单系的，并且这三个“染色质”类群的共同祖先通过一种红色的细菌的内共生捕获了含有叶绿素a和c的质体。迄今为止，基于细胞核基因的分子系统发育分析尚未发现隐藻与附着植物之间存在明显的姐妹关系，但隐藻与单细胞真核生物之间存在明显的亲缘关系，而隐藻与单细胞真核生物中的一个小类群-我们目前购买了两个培养菌株的katablepharids，如Leucocyrptos marina和Katablepharids japonica，并在我们的实验室培养这些细胞，以确定标记基因的xenogeny从两个katablepharids。在最初的研究项目中，我们计划 ...更多信息制备这些细胞的cDNA文库，并对文库进行表达序列标签（EST）测序。遗憾的是，迄今为止还没有文库可用，因为很难从提取自katablepharids细胞的cDNA中除去猎物（附着菌）细胞的核酸样品。然而，我们成功地从L.码头有趣的是，在初步的EF 2系统发育中重建了附着菌、隐藻和可分解藻类的健壮进化枝，并且该进化枝进一步显示出对藻类和绿色植物的亲和力。从EF 2分析得到的树状拓扑结构表明，附着植物、隐藻和katablepharids确实具有共同的祖先，排除了其他真核生物，并且EF 2基因从属于植物的谱系横向转移到附着植物、隐藻和katablepharids的祖先细胞。另一方面，系统发育的EFL基因拒绝单系的haptophytes，隐藻，katablepharids，表明这三个谱系独立收购EFL基因从三个不同的来源。少