In the supplementary information, the primer sequences for sox9a in Table S1 were not correct.
sox9a forward primer (5′→3′), GTCTGATGCACCCAGTCCG; sox9a reverse primer (5′→3′), TCCTTCTTGAAGTCTCCGAGC.
sox9a forward primer (5′→3′), AGTCCACACGTTTCCTGATTG; sox9a reverse primer (5′→3′), ATCCTGTGGAATTCTGTGACG.
The online supplementary PDF has been updated.
The authors apologise to readers for this error and for any inconvenience it may have caused.