The Phaeodactylum genome reveals the evolutionary history of diatom genomes
The Phaeodactylum genome reveals the evolutionary history of diatom genomes
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DOI：
10.1038/nature07410
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发表时间：
2008-11-13
期刊：
影响因子：
64.8
通讯作者：
Grigoriev, Igor V.
中科院分区：
文献类型：
--
作者：
Bowler, Chris;Allen, Andrew E.;Grigoriev, Igor V.
硅藻是在海洋和淡水环境中发现的具有光合作用的次生内生共生体，被认为是地球上约五分之一的初级生产力的来源(1，2)。最近报道了海洋中心硅藻假性海链藻的基因组序列，揭示了丰富的硅藻生物学信息(3-5)。在这里，我们报道了羽状硅藻三角褐指藻的全基因组序列，并将其与假褐指藻进行比较，以阐明这些特征的进化起源、功能意义和在硅藻中的普遍存在。尽管羽状血统和中心血统只分化了9000万年，但它们的基因组结构截然不同，很大一部分基因(类似于40%)并不是由这两个血统的代表共享的。与酵母菌和后生动物的分子差异分析表明，硅藻的基因多样性速度很快。促成因素包括选择性基因家族的扩张，基因和内含子的差异损失和获得，以及转座元件的差异动员。最重要的是，我们记录了来自细菌的数百个基因的存在。在这两种硅藻中都发现了300多种这样的基因转移，证明了它们的古老起源，其中许多可能为代谢物管理和环境信号的感知提供了新的可能性。这些发现有助于解释当代海洋中硅藻令人难以置信的多样性和成功。
Diatoms are photosynthetic secondary endosymbionts found throughout marine and freshwater environments, and are believed to be responsible for around one- fifth of the primary productivity on Earth(1,2). The genome sequence of the marine centric diatom Thalassiosira pseudonana was recently reported, revealing a wealth of information about diatom biology(3-5). Here we report the complete genome sequence of the pennate diatom Phaeodactylum tricornutum and compare it with that of T. pseudonana to clarify evolutionary origins, functional significance and ubiquity of these features throughout diatoms. In spite of the fact that the pennate and centric lineages have only been diverging for 90 million years, their genome structures are dramatically different and a substantial fraction of genes (similar to 40%) are not shared by these representatives of the two lineages. Analysis of molecular divergence compared with yeasts and metazoans reveals rapid rates of gene diversification in diatoms. Contributing factors include selective gene family expansions, differential losses and gains of genes and introns, and differential mobilization of transposable elements. Most significantly, we document the presence of hundreds of genes from bacteria. More than 300 of these gene transfers are found in both diatoms, attesting to their ancient origins, and many are likely to provide novel possibilities for metabolite management and for perception of environmental signals. These findings go a long way towards explaining the incredible diversity and success of the diatoms in contemporary oceans.