Modularity Enhances the Rate of Evolution in a Rugged Fitness Landscape

TL;DR

This paper develops a theoretical model showing that modularity in biological systems accelerates evolution, especially in rugged fitness landscapes, with applications to viral evolution and immune system interactions.

Contribution

It introduces an analytical theory linking modularity and horizontal gene transfer to faster evolution in rugged landscapes, explaining the prevalence of modularity in biology.

Findings

Modularity increases the rate of evolution in rugged landscapes.

Horizontal gene transfer couples with modularity to accelerate evolution.

Approximately 25% of influenza's fitness increase is due to modular protein landscapes.

Abstract

Biological systems are modular, and this modularity affects the evolution of biological systems over time and in different environments. We here develop a theory for the dynamics of evolution in a rugged, modular fitness landscape. We show analytically how horizontal gene transfer couples to the modularity in the system and leads to more rapid rates of evolution at short times. The model, in general, analytically demonstrates a selective pressure for the prevalence of modularity in biology. We use this model to show how the evolution of the influenza virus is affected by the modularity of the proteins that are recognized by the human immune system. Approximately 25\% of the observed rate of fitness increase of the virus could be ascribed to a modular viral landscape.