Modular co-evolution of metabolic networks

TL;DR

This study reveals that the human metabolic network is highly modular with a core-periphery structure, where peripheral modules evolve faster and more cohesively, linking network architecture to evolutionary and functional aspects.

Contribution

It provides a novel topological analysis of human metabolic network modularity and its relation to evolutionary dynamics, highlighting the distinct behaviors of core and peripheral modules.

Findings

Metabolic network exhibits a core-periphery modular structure.

Over half of the modules show co-evolutionary features.

Peripheral modules evolve faster and more cohesively than core modules.

Abstract

The architecture of biological networks has been reported to exhibit high level of modularity, and to some extent, topological modules of networks overlap with known functional modules. However, how the modular topology of the molecular network affects the evolution of its member proteins remains unclear. In this work, the functional and evolutionary modularity of Homo sapiens (H. sapiens) metabolic network were investigated from a topological point of view. Network decomposition shows that the metabolic network is organized in a highly modular core-periphery way, in which the core modules are tightly linked together and perform basic metabolism functions, whereas the periphery modules only interact with few modules and accomplish relatively independent and specialized functions. Moreover, over half of the modules exhibit co-evolutionary feature and belong to specific evolutionary ages. Peripheral modules tend to evolve more cohesively and faster than core modules do. The correlation between functional, evolutionary and topological modularity suggests that the evolutionary history and functional requirements of metabolic systems have been imprinted in the architecture of metabolic networks. Such systems level analysis could demonstrate how the evolution of genes may be placed in a genome-scale network context, giving a novel perspective on molecular evolution.