show Abstracthide AbstractDespite deep evolutionary conservation, recombination varies greatly across the genome, among individuals, sexes and populations and can be a major evolutionary force in the wild. Yet this variation in recombination and its impact on adaptively diverging populations is not well understood. To elucidate the nature and potential consequences of recombination rate variation, we characterized fine-scale recombination landscapes by combining pedigrees, functional genomics and field fitness measurements in an adaptively divergent pair of marine and freshwater threespine stickleback populations from River Tyne, Scotland. Through whole-genome sequencing of large nuclear families, we identified the genomic location of almost 50,000 crossovers and built recombination maps for 36 marine, freshwater, and hybrid individuals at 3.8 kilobase resolution. Using these maps, we quantified the factors driving variation in recombination rate.