Recombination data for the repeat-based holocentromere-harbouring genome of R. breviuscula

Centromeres strongly affect (epi)genomic architecture and meiotic
recombination dynamics influencing the overall distribution and frequency
of crossovers. Here, we studied how recombination is regulated and
distributed in the holocentric plant Rhynchospora breviuscula, a species
lacking localised 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. Our results hint at the primary influence of mechanistic
features of meiotic pairing and synapsis rather than (epi)genomic features
and centromere organisation in determining the distally-biased crossover
distribution in R. breviuscula. While centromeres and (epi)genetic
properties only affect crossover positioning locally.