Live and let die: centromere loss during evolution of plant chromosomes

Functional centromeres, ensuring regular chromosome segregation in mitosis and meiosis, are a prerequisite for the evolutionary success of pre-existing and new chromosome variants. The rapid progress in plant comparative genomics and cytogenetics brings new insights into the evolutionary fate of centromeres and mechanisms of chromosome number reduction (descending dysploidy). Centromere loss and relocation in chromosome regions with otherwise conserved collinearity can be explained by conventional mechanisms of chromosome rearrangements or, as newly available phylogenomic and cytogenomic data suggest, by centromere inactivation through epigenetic chromatin modifications and/or intra-and inter-chromosomal recombination.