Quantitative analysis of redundancy in evolution of developmental systems

Redundancy is believed to play a key role in robustness and evolvability of biological systems. This paper investigates the influence of redundancy on the evolutionary performance of a gene regulatory network governing a cellular growth process. Extensive simulation results suggest that, for the developmental model studied in this work, maintaining sufficient redundancy helps to improve the ability of the evolutionary algorithm to achieve better performance. To examine the change of redundancy during the evolutionary process and its relationship to evolutionary performance, we propose a quantitative definition for measuring different aspects of redundancy, namely, structural redundancy, functional redundancy and functional proximity. Our results show that evolution attempts to increase the functional redundancy after pruning of redundant genes if the evolution is under a larger selection pressure. It is also interesting to notice that an increase in functional proximity enhances the evolutionary performance.