n page 765, Ohzeki et al. present evidence for sequence specificity in assembling chromatin at mammalian centromeres. The sequence requirements imply that construction of centromeric chromatin is more than an epigenetic process. O Centromeric chromatin assembles at AT-rich repeats called ␣ satellite sequences, or alphoids. Type I alphoids contain boxes for the binding of CENP-B, one of several ...