硅藻是海洋與淡水中的一種微型藻類,，在海洋中居支配地位,，占地球上初級生產(chǎn)力的約1/5,。本期Nature發(fā)布了三角褐指藻（Phaeodactylum tricornutum）的完整基因組序列，它是第二個(gè)被測序的硅藻,。與第一個(gè)被測序的硅藻——假微型海鏈藻（Thalassiosira pseudonana）所做的對比表明,，通過硅藻與細(xì)菌之間的雙向基因轉(zhuǎn)移，硅藻從細(xì)菌獲得了數(shù)百個(gè)基因,?；蜣D(zhuǎn)移在硅藻演化中似乎是普遍存在的,，產(chǎn)生了基因的非正規(guī)組合（其中包括一些來自植物和動(dòng)物的基因），很可能在營養(yǎng)管理和環(huán)境信號(hào)作用中起重要作用,。（生物谷Bioon.com）
生物谷推薦原始出處：
Nature 456, 239-244 (13 November 2008) | doi:10.1038/nature07410
The Phaeodactylum genome reveals the evolutionary history of diatom genomes
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 Earth1, 2. The genome sequence of the marine centric diatom Thalassiosira pseudonana was recently reported, revealing a wealth of information about diatom biology3, 4, 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 (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.
