Nat. Struct. Mol. Biol. 19, 948–956 (2012); published online 26 August 2012; corrected after print 27 December 2012

In the version of this article initially published, the colors in the key in Figure 7c were incorrectly reversed. Red should have represented telomeres and gray a-satellite regions. The error has been corrected in the HTML and PDF versions of the article.