Author Correction: Sister chromatid resolution is an intrinsic part of chromosome organization in prophase.

In the version of this Letter originally published, the authors omitted a citation of an early study demonstrating topoisomerase-II-dependent sister chromatid resolution. This reference has now been added to the reference list as reference number 28, and the relevant text has been amended as follows to include its citation: 'Resolution must reflect the removal of sister-sister contacts, and we show here that Topo-IIα-mediated release of DNA catenation plays a major role (Fig. 4), in agreement with previous findings28 , whereas, surprisingly, cohesin dissociation is not strictly required (Fig. 3).' Subsequent references have been renumbered. All online versions of the Letter have been updated to reflect this change.