Annotation:
While most eukaryotes contain single regional centromeres, several plant and animal lineages assemble holocentromeres along the entire chromosome length. In our study, we assembled genomes of three beak sedges (
Rhynchospora pubera,
R. breviuscula, and
R. tenuis) with repeat-based holocentromeres as well as a genome of their closest monocentric relative,
Juncus effusus, and compared their genome organization and evolution as a function of centromere type. We demonstrate that transition to holocentricity influenced the 3D (epi)genome architecture by redefining genomic compartments, while distributing centromere function to thousands of repeat-based centromere units genome-wide. We also show that chromosome fusions, facilitated by repeat-based holocentromeres, promoted karyotype evolution and diploidization. The study thus shed light on several important aspects of genome architecture and evolution influenced by centromere organization.
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