The evolution of the metabolic network over long timelines

Metabolism is executed by an efficient, interconnected and ancient biochemical system, the metabolic network. Its evolutionary origins are, however, barely understood. We here discuss that because of niche adaptation, selection acting on network structure distinguishes modern species early life forms. Yet, its basic remained conserved over more than three billion years diverging evolution. speculate this situation attributes key roles in evolution to (i) reaction properties central metabolites, (ii) simple catalysts (e.g. metal ions, amino acids) whose importance unchanged during evolution, (iii) interconnectivity limits expansion. The conservation hence implies forms already used similar topologies as species.