Nature 523, 212–216 (2015); doi:10.1038/nature14465

The y-axis label in Fig. 3f of this Letter should read ‘[mCAC/CAC]/[mCAG/CAG]’ rather than ‘[mCAC/CAC]/[mCAC/CAG]’. In addition, in the description of Fig. 4c in the main text, ‘tissue’ and ‘individual’ were swapped; it should read, “Of the ASM events that varied, 4.1–7.5% and 54.5–70.0% were tissue- and individual-variable, respectively;”. These errors have been corrected in the online versions of the paper.