PT - JOURNAL ARTICLE AU - Kevin Brick AU - Sarah Thibault-Sennett AU - Fatima Smagulova AU - Kwan-Wood G. Lam AU - Yongmei Pu AU - Florencia Pratto AU - R. Daniel Camerini-Otero AU - Galina V. Petukhova TI - Extensive sex differences at the initiation of genetic recombination AID - 10.1101/235002 DP - 2017 Jan 01 TA - bioRxiv PG - 235002 4099 - http://biorxiv.org/content/early/2017/12/26/235002.short 4100 - http://biorxiv.org/content/early/2017/12/26/235002.full AB - Homologous recombination in meiosis is initiated by programmed DNA double strand breaks (DSBs) and DSB repair as a crossover is essential to prevent chromosomal abnormalities in gametes. Sex differences in recombination have been previously observed by analyses of recombination end-products. To understand when and how sex differences are established, we built genome-wide maps of meiotic DSBs in both male and female mice. We found that most recombination initiates at sex-biased DSB hotspots. Local context, the choice of DSB targeting pathway and sex-specific patterns of DNA methylation give rise to these differences. Sex differences are not limited to the initiation stage, as the rate at which DSBs are repaired as crossovers appears to differ between the sexes in distal regions. This uneven repair patterning may be linked to the higher aneuploidy rate in females. Together, these data demonstrate that sex differences occur early in meiotic recombination.