Nature 493, 216–220 (2013); doi:10.1038/nature11690

In this Letter, Mark J. Rieder (Department of Genome Sciences, University of Washington, Seattle, Washington 98195, USA) was inadvertently omitted from the author list. He oversaw data generation and quality control and is a member of the Seattle Grand Opportunity group. The error has been corrected in the HTML and PDF versions of the paper online.