Poster Sessions

GENO -15

Pavel Khil

P. Khil, R. D. Camerini-Otero

A genome-wide analysis reveals rapid changes in human meiotic recombination hotspots

Meiotic recombination is initiated by the introduction of programmed double stranded breaks (DSBs) early in meiosis. A commonly observed feature of meiotic recombination is the highly non-uniform distribution of meiotic crossovers in the genome. It is still not clear, however, why crossovers are preferentially localized in hotspots instead of being uniformly distributed. To study the mechanisms responsible for the formation and disappearance of meiotic hotspots of recombination we compared computed recombination rate profiles between four human populations sampled by the HapMap project and found that more than 10% of hotspots of recombination vary among populations. Then we asked how well these computed \"historical\" hotspots calculated from patterns of linkage disequilibrium predict genetic crossovers in present-day individuals. We find that up to 30-40% of present-day crossovers are located in regions without \"historical\" hotspots. In addition, we find that genetic crossovers are better predicted by the computed recombination profile of the cognate population. The observed differences among populations and between historic hotspots of recombination and present-day crossovers indicate that profiles of recombination are changing rapidly over time. We believe that this degree of a polymorphism of recombination hotspots most likely reflects DNA sequence changes in distant elements or epigenetic factors.