The evolutionary advantage of fitness‐dependent recombination in diploids: A deterministic mutation–selection balance model

Abstract

Recombination's omnipresence in nature is one of the most intriguing problems in evolutionary biology. The question of why recombination exhibits certain general features is no less interesting than that of why it exists at all. One such feature is recombination's fitness dependence (FD). The so far developed population genetics models have focused on the evolution of FD recombination mainly in haploids, although the empirical evidence for this phenomenon comes mostly from diploids. Using numerical analysis of modifier models for infinite panmictic populations, we show here that FD recombination can be evolutionarily advantageous in diploids subjected to purifying selection. We ascribe this advantage to the differential rate of disruption of lower‐ versus higher‐fitness genotypes, which can be manifested in selected systems with at least three loci. We also show that if the modifier is linked to such selected system, it can additionally benefit from modifying this linkage in a fitness‐dependent manner. The revealed evolutionary advantage of FD recombination appeared robust to crossover interference within the selected system, either positive or negative. Remarkably, FD recombination was often favored in situations where any constant nonzero recombination was evolutionarily disfavored, implying a relaxation of the rather strict constraints on major parameters (e.g., selection intensity and epistasis) required for the evolutionary advantage of nonzero recombination formulated by classical models.

Fitness dependence preserves selection for recombination across diverse mixed mating systems

“…S4). This is consistent with the analogous results of other studies [8,13] and is expected given that the impact of fitness dependence is limited by the frequency of individuals carrying multiple mutations.…”

Selection for Plastic, Pathogen-Inducible Recombination in a Red Queen Model with Diploid Antagonists

“…Notably, in such situations, plastic recombination is favored despite the above-discussed cost of moving the population’s mean recombination rate from the optimum. This finding expands our recent results showing that fitness-dependent recombination can save recombination from disappearing under purifying selection in mutation-selection models [ 62 , 63 ].…”

“…The other aspect is whether and to which extent recombination per se and its plasticity to environmental stressors, including pathogens, are modulated by genotype fitness. To address this question, we need to model larger genetic systems, with at least three selected loci, which can provide the required variation in fitness across genotypes [ 41 , 62 ].…”

Shift-inducible [transgenerational] increase in recombination rate as an evolving strategy in a periodic environment: a numerical model

“…A pure setup should allow for only one component of RR variation. Thus, to demonstrate the advantage of the between-genotype variation in RR alone, one should assume a constant environment, which was indeed done in several mutation-selection balance models [38,39]. In the current study, we, in contrast, exclude the between-genotype variation in RR: The only source of stress in our model is environmental shifts, and this transient stress equally affects all population members.…”