Sequencing and comparative genomics of closely related Biscutella laevigata species
Beyond their fundamental importance for the segregation of chromosomes, centromeres and their evolution remain elusive. In plants, flanking (pericentromeric) segments are characterized by low recombination and chiefly constituted of gypsy retrotransposons. Although such distribution expectedly results from an equilibrium between the insertion of new copies and their removal by purifying selection in high-recombining segments away from the centromere, empirical evidence remains scarce. Chromosome-scale assemblies characterizing the gene space and repetitive fraction of three diploids within the highly-polymorphic species Biscutella leavigata and one outgroup species were used to assess the evolution of retrotransposons around centromeres.