Mutational Robustness - Robustness and Evolvability

Robustness and Evolvability

Mutational Robustness appears to have a negative impact on evolvability because it reduces the mutational accessibility of distinct heritable phenotypes for a single genotype and reduces selective differences within a genetically diverse population. Counter intuitively however, it has been hypothesized that phenotypic robustness towards mutations may actually increase the pace of heritable phenotypic adaptation when viewed over longer periods of time. The hypothesis put forth is that connected networks of fitness neutral genotypes result in mutational robustness and reduced accessibility of heritable phenotypes over short timescales. On the other hand over longer periods of time, genetic drift combined with neutral/buffered mutations can provide mutational access to a greater number of distinct heritable phenotypes that are reached from different points of the genetic neutral network. This hypothesis is supported by simulations of biological systems. and appears consistent with the available data on biomolecular evolution Simulations have indicated that positive relationships between mutational robustness and evolvability can be facilitated by degeneracy within biological systems.