Nature 552, 239–243 (2017); doi:https://doi.org/10.1038/nature24675

In this Letter, owing to an error during the production process, the keys to the bar charts in Extended Data Fig. 4c, h, k, n and q all appeared as open white boxes, instead of displaying the different colours used in graphs (for example, to denote the ‘polarized’ and ‘non-polarized’ sections, or the ‘lumen’, ‘rosette’ and ‘disorganized’ sections). In addition, in Extended Data Fig. 4k, the colours in the graph (to denote the ‘lumen’, ‘rosette’ and ‘disorganised’) were also missing. This figure has been corrected online.