Rapid evolution of fine-scale recombination during domestication: a perspective from population genomics

Recombination serves as a pivotal force propelling the evolution of genomic diversity in sexually reproducing organisms. Despite its fundamental role, the evolutionary dynamics of recombination rates and their implications for genome evolution remain largely elusive. The domestication of animals, which is characterized by dynamic selection pressures, offers a unique lens to explore this issue. Here, we constructed a fine-scale recombination map leveraging whole-genome data from domestic chickens, encompassing both contemporary commercial breeds and the wild progenitor, the Red Junglefowl (RJF). Our analysis revealed the rapid evolution of the recombination landscape within and across chicken populations, with significant variation in recombination coldspots and hotspots, particularly in commercial breeds. The occurrence of coldspots and the disappearance of hotspots are closely associated with selective sweeps.Contrary to prevailing observations in most species, we observed a weakly negative correlation between recombination rates and the frequency of introgressed ancestry from other RJF subspecies. Our findings provide valuable insights into the intricate interplay of evolutionary forces shaping the evolution of recombination.