202. Sex differences in recombination maps are associated with differential hotspot usage in sheep

Abstract

Recombination is a fundamental biological process for the reproduction and evolution of species. Recombination phenotypes have been shown to exhibit large inter-individual variation with a significant genetic determinism. Here we make use of large genotyping datasets in the Sheep to: (1) study the distribution of recombinations along the genome (recombination maps); and (2) evaluate its inter-individual variation using a phenotype termed hotspot usage (HSU). We precisely estimated sex specific recombination maps and found that sex differences in recombination rates are concentrated in 16% of the genome, mostly at chromosome extremities. Individual variation in HSU is dominated by a large difference between sexes: males are found to preferentially use recombination hotspots contrary to females. This difference is most pronounced in regions with large sex differences in recombination rate. This suggests that sex difference in recombination maps in Sheep could be due to different crossover determination processes in male and female meioses.