There was an error published in Biol. Open4, 980-992.

The statements regarding funding were incomplete and the following text has now been included in the Funding section:

This work was supported by the Fondation pour la Recherche Médicale, grant number [DEQ20140329501] to P.D.

Biology Open and the authors apologise to the readers for any confusion that this omission might have caused.

This is an Open Access article distributed under the terms of the Creative Commons Attribution License (, which permits unrestricted use, distribution and reproduction in any medium provided that the original work is properly attributed.