Metabolic network modularity arising from simple growth processes

TL;DR

This paper presents a simple, parameter-free evolving network model demonstrating that metabolic network modularity can emerge from basic growth processes, challenging previous theories that linked modularity to evolutionary goal changes.

Contribution

The study introduces a new model showing metabolic network modularity arises from simple growth, independent of evolutionary goal shifts, broadening understanding of metabolic evolution.

Findings

Metabolic modularity can emerge from simple growth processes.

The model applies across various organisms.

Modularity is less dependent on evolutionary goal changes.

Abstract

Metabolic networks consist of linked functional components, or modules. The mechanism underlying metabolic network modularity is of great interest not only to researchers of basic science but also to those in fields of engineering. Previous studies have suggested a theoretical model, which proposes that a change in the evolutionary goal (system-specific purpose) increases network modularity, and this hypothesis was supported by statistical data analysis. Nevertheless, further investigation has uncovered additional possibilities that might explain the origin of network modularity. In this work, we propose an evolving network model without tuning parameters to describe metabolic networks. We demonstrate, quantitatively, that metabolic network modularity can arise from simple growth processes, independent of the change in the evolutionary goal. Our model is applicable to a wide range of organisms, and appears to suggest that metabolic network modularity can be more simply determined than previously thought. Nonetheless, our proposition does not serve to contradict the previous model; it strives to provide an insight from a different angle in the ongoing efforts to understand metabolic evolution, with the hope of eventually achieving the synthetic engineering of metabolic networks.