Nat. Biotechnol. 35, 1016–1020 (2017); published online 9 November 2017; corrected after print 14 December 2017

In the version of this article initially published, on p.1019, Yurttas Beim's name was misspelled as “Biem,” and on p.1020, Hank Greely's last name was misspelled as “Greeley” twice. The errors have been corrected in the HTML and PDF versions of the article.