Comment on

• Retinoic acid signalling links left-right asymmetric patterning and bilaterally symmetric somitogenesis in the zebrafish embryo.

  Kawakami Y, Raya A, Raya RM, Rodríguez-Esteban C, Izpisúa Belmonte JC. Kawakami Y, et al. Nature. 2005 May 12;435(7039):165-71. doi: 10.1038/nature03512. Nature. 2005. PMID: 15889082
• FGF-induced vesicular release of Sonic hedgehog and retinoic acid in leftward nodal flow is critical for left-right determination.

  Tanaka Y, Okada Y, Hirokawa N. Tanaka Y, et al. Nature. 2005 May 12;435(7039):172-7. doi: 10.1038/nature03494. Nature. 2005. PMID: 15889083
• Retinoic acid coordinates somitogenesis and left-right patterning in vertebrate embryos.

  Vermot J, Pourquié O. Vermot J, et al. Nature. 2005 May 12;435(7039):215-20. doi: 10.1038/nature03488. Nature. 2005. PMID: 15889094