There was an error published in the ePress version of Development138, 3915-3920 published on 10 August 2011.
On p. 3919, in the legend for Fig. 4, asymmetry was incorrectly referred to as symmetry. The correct sentence appears in full below:
Subsequently, nodal cilia develop and nodal flow is generated, which triggers the establishment of left-right asymmetry.
The replacement ePress article published on 17 August 2011, the online issue and print copy are correct.
We apologise to authors and readers for this error.