Post-translational modifications of core histones, particularly in the N terminus, seem to define different chromatin states in the genome. For instance, actively transcribed regions of euchromatin have a completely different set of 'marks' compared with silent heterochromatin. Recent analyses surprisingly demonstrate that, in addition to containing the histone H3 variant CENP-A, the centromeric chromatin that underlies the kinetochore bears a distinct combination of histone H3 modifications.