Nat. Biotechnol. 32, 724–726 (2014); published online 7 August 2014; corrected after print 10 October 2014; 10.1038/nbt.2973

In the version of this article initially published, two author names were misspelled: the correct names are Cavagnaro, not Cavanagro; Feigal not Feigel. In addition, the name for the Health Insurance Portability and Accountability Act (HIPAA) was given as Health Insurance Portability and Privacy Act (HIPPA). The errors have been corrected in the HTML and PDF versions of the article.