Adaptive evolution of bacterial metabolic networks by horizontal gene transfer
Adaptive evolution of bacterial metabolic networks by horizontal gene transfer
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DOI：
10.1038/ng1686
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发表时间：
2005-12-01
期刊：
影响因子：
30.8
通讯作者：
Lercher, MJ
中科院分区：
文献类型：
--
作者：
Pál, C;Papp, B;Lercher, MJ
许多研究已经考虑到代谢途径的出现(1)，但代谢网络的近期进化模式却知之甚少。在这里，我们将比较基因组学与通量平衡分析相结合，以检验(i)不同遗传机制对细菌网络生长的贡献，（ii）驱动网络进化的选择力，以及（iii）新节点融入网络。在过去的1亿年里，大肠杆菌代谢网络的大部分变化是由于水平基因转移，基因复制的贡献很小。在适应不断变化的环境的驱动下，网络通过获取参与运输和催化外部营养物质的基因而增长。因此，水平转移的基因被整合在网络的外围，而中心部分则保持进化稳定。编码生理偶联反应的基因通常在一起转移，通常在操纵子中。因此，细菌代谢网络通过直接吸收外周反应来进化，以应对变化的环境。
Numerous studies have considered the emergence of metabolic pathways(1), but the modes of recent evolution of metabolic networks are poorly understood. Here, we integrate comparative genomics with flux balance analysis to examine (i) the contribution of different genetic mechanisms to network growth in bacteria, (ii) the selective forces driving network evolution and (iii) the integration of new nodes into the network. Most changes to the metabolic network of Escherichia coli in the past 100 million years are due to horizontal gene transfer, with little contribution from gene duplicates. Networks grow by acquiring genes involved in the transport and catalysis of external nutrients, driven by adaptations to changing environments. Accordingly, horizontally transferred genes are integrated at the periphery of the network, whereas central parts remain evolutionarily stable. Genes encoding physiologically coupled reactions are often transferred together, frequently in operons. Thus, bacterial metabolic networks evolve by direct uptake of peripheral reactions in response to changed environments.