Intra- and intermolecular chromatin springs. (A) A bioriented sister chromatid pair under tension in metaphase is shown as containing both intramolecular springs (pericentromere loop in blue) and intermolecular springs (sister cohesion in red; left) or only intermolecular springs (right). (B) A mid-anaphase spindle with a dicentric chromosome bridge. Cohesin is cleaved, and monocentric chromosomes move to the spindle poles. The two centromeres on the same chromatid attach to opposite spindle poles, thereby creating a double-stranded DNA chromosome bridge. Cell cycle progression is delayed in mid-anaphase for ∼45 min (Yang et al., 1997). (C) Variation in spindle length is graphed for WT and the active dicentric (data replotted from Fig. 2 B). The asterisk denotes that they are statistically different (P < 0.05). The error bars represent 95% confidence.