Degeneracy: a design principle for achieving robustness and evolvability

TL;DR

This paper investigates how degeneracy, a form of partial redundancy, enhances the evolvability of biological systems, showing that it is a key design principle for balancing robustness and adaptability.

Contribution

It demonstrates through simulations that degeneracy significantly increases evolvability compared to pure redundancy, highlighting its role in natural evolution.

Findings

Degenerate systems are more evolvable than purely redundant ones.

Neutral network size and topology do not explain variations in evolvability.

Degeneracy may be a fundamental enabler of biological innovation.

Abstract

Robustness, the insensitivity of some of a biological system's functionalities to a set of distinct conditions, is intimately linked to fitness. Recent studies suggest that it may also play a vital role in enabling the evolution of species. Increasing robustness, so is proposed, can lead to the emergence of evolvability if evolution proceeds over a neutral network that extends far throughout the fitness landscape. Here, we show that the design principles used to achieve robustness dramatically influence whether robustness leads to evolvability. In simulation experiments, we find that purely redundant systems have remarkably low evolvability while degenerate, i.e. partially redundant, systems tend to be orders of magnitude more evolvable. Surprisingly, the magnitude of observed variation in evolvability can neither be explained by differences in the size nor the topology of the neutral networks. This suggests that degeneracy, a ubiquitous characteristic in biological systems, may be an important enabler of natural evolution. More generally, our study provides valuable new clues about the origin of innovations in complex adaptive systems.