Correction to: Nature Reviews Molecular Cell Biology (2021) https://doi.org/10.1038/s41580-021-00356-8, published online 09 April 2021.

The first sentence under the subheading ‘Regulating developmental stages’ has been updated to clarify that the early syncytial embryos referred to are from C. elegans, and that the smFISH and MS2–MCP studies mentioned extend previous observations summarized in reference 24. These changes have been made in the HTML and PDF versions of the article.