Synthetic and Systems Biology Unit, Institute of Biochemistry, Biological Research Centre of the Hungarian Academy of Sciences, Temesvári krt. 62, Szeged H-6726, Hungary.
Department for Computer Science, Heinrich Heine University, Universitätsstraße 1, Düsseldorf D-40221, Germany.
Nat Commun. 2016 May 20;7:11607. doi: 10.1038/ncomms11607.
A central challenge in evolutionary biology concerns the mechanisms by which complex metabolic innovations requiring multiple mutations arise. Here, we propose that metabolic innovations accessible through the addition of a single reaction serve as stepping stones towards the later establishment of complex metabolic features in another environment. We demonstrate the feasibility of this hypothesis through three complementary analyses. First, using genome-scale metabolic modelling, we show that complex metabolic innovations in Escherichia coli can arise via changing nutrient conditions. Second, using phylogenetic approaches, we demonstrate that the acquisition patterns of complex metabolic pathways during the evolutionary history of bacterial genomes support the hypothesis. Third, we show how adaptation of laboratory populations of E. coli to one carbon source facilitates the later adaptation to another carbon source. Our work demonstrates how complex innovations can evolve through series of adaptive steps without the need to invoke non-adaptive processes.
进化生物学中的一个核心挑战涉及到需要多个突变才能产生的复杂代谢创新的机制。在这里，我们提出，通过添加一个单一反应即可获得的代谢创新，可以作为在另一种环境中建立复杂代谢特征的垫脚石。我们通过三个互补的分析来证明这一假设的可行性。首先，我们使用基因组规模的代谢建模，表明大肠杆菌中复杂的代谢创新可以通过改变营养条件而产生。其次，我们使用系统发育方法，证明了在细菌基因组的进化历史中，复杂代谢途径的获取模式支持这一假设。第三，我们展示了实验室大肠杆菌种群对一种碳源的适应如何促进对另一种碳源的适应。我们的工作表明，复杂的创新如何通过一系列适应性步骤进化，而不需要引入非适应性过程。
