Nature 550, 255–259 (2017); doi:10.1038/nature24042

Owing to an error during the production process, in Fig. 2c of this Letter, all four groups of mice were incorrectly labelled as ‘WT’ (wild type), but the two groups on the left (filled and open blue boxes) should have been labelled ‘WT’, whereas the two groups on the right (filled and open yellow boxes) should have been labelled ‘KO’ (knockout), as in the key for Fig. 2b. The original Letter has been corrected online.