There was an error published in Development136, 1179-1189.

On page 1181, it was incorrectly stated that We confirmed previous studies showing that Six3 is expressed in a dynamic pattern during development of Paracentrotus lividus (Poustka et al., 2007), a species closely related to Strongylocentrotus purpuratus used in this study.'

It should have stated We confirmed previous studies showing that Six3 is expressed in a dynamic pattern during development of Strongylocentrotus purpuratus (Poustka et al., 2007).'

The authors apologise to readers for this mistake.