Selection Can Favor a Recombination Landscape That Limits Polygenic Adaptation
Tom Parée, Luke Noble, Denis Roze, Henrique Teotónio.
Abstract
Modifiers of recombination rates have been described but the selective pressures acting on them and their effect on adaptation to novel environments remain unclear. We performed experimental evolution in the nematode Caenorhabditis elegans using alternative rec-1 alleles modifying the position of meiotic crossovers along chromosomes without detectable direct fitness effects. We show that adaptation to a novel environment is impaired by the allele that decreases recombination rates in the genomic regions containing fitness variation. However, the allele that impairs adaptation is indirectly favored by selection, because it increases recombination rates and reduces the associations among beneficial and deleterious variation located in its chromosomal vicinity. These results validate theoretical expectations about the evolution of recombination but suggest that genome-wide polygenic adaptation is of little consequence to indirect selection on recombination rate modifiers.
Keywords : C. elegans ; rec-1 ; epistasis ; experimental evolution ; genomic heritability ; indirect selection ; linked selection ; meiotic crossover ; polygenic adaptation ; population genomics ; recombination ; the Hill–Robertson effect.
Mol Biol Evol. 2025 Jan 6 ;42(1):msae273. doi : 10.1093/molbev/msae273.
