Journal of Computer Science & Systems Biology

The maintenance of sex has long been a mystery to evolutionary biology. Though meiotic recombination helps purge deleterious mutations and has a key role in generating evolutionary innovations, it is not clear that these benefits can recoup costs of sex and recombination. By employing Wagner’s genetic regulatory network (GRN) model, in this paper, we have been able to test how selection pressure affects the underlying evolutionary dynamics in sexual lineages. In the first study we find that, compared with asexual lineages, low-fitness sexual lineages can gain a higher benefit when they are subject to higher selection pressure, especially at the early stage. These indicate that selection pressure can facilitate a fast adaptation for low-fitness individuals via recombination. In the second study where we include both the recombination cost and the twofold cost (the competitive advantage of asexual lineages relative to sexual lineages) into the system, we show that though recombination is initially costly, it rapidly evolves (through rewiring gene regulation) to compensate in even a single bout for costs of sex and recombination. We further explore the parameter space and find that sexual lineages with low levels of sex and recombination can outcompete strictly asexual populations under higher selection pressure and lower mutation rates. These results have important implications for explaining the maintenance of sex and recombination in the context of genetic networks.