Schematic representation of the sequences on the short arms of human acrocentric chromosomes. Organization of β satellite DNA according to Floustakou et al. [25] and Waye et al. [17]. The region comprising Satellite III pR-1, pR-2, pR-4, perinucleolar β satellite PJ and DJ, NOR and telomeric regions are shared by all acrocentric chromosomes. The most variable region is that of the proximal satellite III, although chromosomes 13, 14, and 21, on one hand, and chromosomes 14 and 22, on the other hand, share sequences. The only chromosome-specific sequence is the satellite III subfamily D15Z1, typical of chromosome 15p. Organization of the subfamilies of satellite III DNA according to Bandyopadhyay et al. [19], Jarmuz et al. [26], Higgins et al. [21], and Choo et al. [27]. Arrows indicate regions that were analyzed by Fluorescence In Situ Hybridization (FISH) in this study.