Investigating Differences in Meiotic Recombination Patterns Between Male and Female Meiosis Using High-Resolution Crossover Mapping in Maize

Meiotic recombination is the main source of genetic variation in evolution as well as in plant and animal breeding. However, despite their importance the resulting crossovers (COs) are not uniformly distributed across the genome, a phenomenon, which is not completely understood. One of the least elucidated aspects of meiotic recombination are differences between CO rates and pattern between male and female meiosis. To investigate these differences, we conducted high-resolution mapping of CO locations using whole-genome sequencing in the maize B73 x Mo17 hybrid. We found that the overall CO rates were similar in the two sexes. However, significant differences between male and female CO rates in several specific genome regions. Furthermore, the placement of the CO in relationship to gene transcription start sites differed between the sexes. We also found that epigenetics factors, such as DNA methylation, nucleosome occupation, and histone modification have similar effects on CO formation in both sexes. These results will help unravel possible mechanisms controlling CO rates and location in plants.