Postdoc University of Florida Gainesville, Florida
Body of Abstract: Meiotic recombination is a fundamental process that generates genetic diversity and has important consequences for population differentiation and speciation. However, the mechanisms underlying genetic and epigenetic regulation of meiotic recombination, particularly between sexes, are still not fully understood in many organisms, including maize. In this study, we have been using 25 parental inbred lines of the maize nested association mapping (NAM) populations to identify variations and factors involved in meiotic recombination between sexes. These inbred lines were selected as they account for more than 85% of intraspecies allelic diversity in maize. To date, we have performed genotyping-by-sequencing (GBS) on 1,728 backcrossed (BC1) individuals derived from nine male and female F1 hybrids. Our data shows that three hybrids have significantly higher crossover numbers and overall recombination rates in male meiosis than in females, particularly in the distal ends of each chromosome, whereas one hybrid has lower recombination in males. For the other five BC1s, we did not observe significant differences in recombination between sexes at the entire genome level, although some differences were found at the chromosome level. Furthermore, the number of crossovers in male meiosis is more variable than in females, which exhibit consistency in the crossover number across the lines. Together, these results suggest that meiotic recombination varies substantially in different maize genetic backgrounds. Additionally, we will construct high-resolution crossover maps and generate genomic and epigenomic data for the lines that have the largest differences in recombination between sexes to elucidate genetic and epigenetic factors involved in regulating sex-specific meiotic recombination.