Nat. Genet. 43, 630–638 (2011); published online 19 June; corrected after print 11 July 2011

In the version of this article initially published, the accession codes section contained inaccuracies. The raw sequences and processed data generated from this study can be downloaded with accession number GSE28247. The previously published histone modification data used in this study are found under accession numbers GSE12241 and GSE11172. The error has been corrected in the HTML and PDF versions of the article.