The origin and evolution of Archaea: a state of the art
The origin and evolution of Archaea: a state of the art
复制标题
DOI：
10.1098/rstb.2006.1841
复制
发表时间：
2006-06-29
影响因子：
6.3
通讯作者：
Brochier-Armanet, Celine
中科院分区：
文献类型：
--
作者：
Gribaldo, Simonetta;Brochier-Armanet, Celine
环境调查表明，古细菌不仅在极端环境中多样化且丰富，而且在土壤、海洋和淡水中也如此，它们可能在地球的生物地球化学循环中发挥关键作用。古细菌表现出独特的能力，例如产甲烷和在高于 90 摄氏度的温度下生存，这使得它们对于了解早期地球生物群的性质至关重要。分子、基因组学和系统发育数据强化了沃斯对古生菌的定义，即除细菌和真核生物之外的第三个生命领域。对不同分子系统组成部分的系统基因组学分析突显了古细菌主要垂直遗传基因的核心。这使得我们能够恢复全球范围内解析良好的古菌进化图景，而不是观察到的细菌和真核生物。这可能是由于当今古菌谱系出现时并未发生快速分化。这种系统发育支持了当今古菌谱系的超嗜热和非产甲烷祖先，以及两个主要门（泉古菌门和广古菌门）之间的深刻分歧，而这在其他两个生命领域可能没有对应的分歧。纳米古菌可能并不代表第三个古菌门，而是一个快速进化的广古菌谱系。产甲烷作用似乎只在广古菌进化的早期出现过一次。通过添加目前未开垦的物种来填补古菌进化的图景，并将其放回到地质时期，仍然是未来的两个基本目标。
Environmental surveys indicate that the Archaea are diverse and abundant not only in extreme environments, but also in soil, oceans and freshwater, where they may fulfil a key role in the biogeochemical cycles of the planet. Archaea display unique capacities, such as methanogenesis and survival at temperatures higher than 90 degrees C, that make them crucial for understanding the nature of the biota of early Earth. Molecular, genomics and phylogenetics data strengthen Woese's definition of Archaea as a third domain of life in addition to Bacteria and Eukarya. Phylogenomics analyses of the components of different molecular systems are highlighting a core of mainly vertically inherited genes in Archaea. This allows recovering a globally well-resolved picture of archaeal evolution, as opposed to what is observed for Bacteria and Eukarya. This may be due to the fact that no rapid divergence occurred at the emergence of present-day archaeal lineages. This phylogeny supports a hyperthermophilic and non-methanogenic ancestor to present-day archaeal lineages, and a profound divergence between two major phyla, the Crenarchaeota and the Euryarchaeota, that may not have an equivalent in the other two domains of life. Nanoarchaea may not represent a third and ancestral archaeal phylum, but a fast-evolving euryarchaeal lineage. Methanogenesis seems to have appeared only once and early in the evolution of Euryarchaeota. Filling up this picture of archaeal evolution by adding presently uncultivated species, and placing it back in geological time remain two essential goals for the future.