Meiotic recombination dynamics in holocentric Rhynchospora breviuscula

Centromeres strongly affect (epi)genomic architecture and meiotic recombination dynamics, influencing crossovers' overall distribution and frequency. We studied how recombination is regulated and distributed in the holocentric plant Rhynchospora breviuscula, a species with diffused centromeres. Combining immunocytochemistry, chromatin analysis, and high-throughput single-pollen sequencing, we discovered that crossover frequency is distally biased, in sharp contrast with the diffused distribution of hundreds of centromeric units and (epi)genomic features. Remarkably, we found that crossovers were abolished inside centromeric units but not in their proximity indicating the absence of a canonical centromere effect. We further show that telomere-led synapsis of homologs is the feature that best explains the observed recombination landscape.