Externally the vertebrate body plan presents a bilateral symmetry in relation to the midline. However, inside the body the distribution of the visceral organs follows a very particular pattern that is not symmetrical in relation to the midline.

The last 10 years have seen remarkable advances in our understanding of how the internal asymmetries typical of the vertebrate body are established and controlled. The use of different development models has permitted to uncover fascinating ways of creating asymmetry, like the activity of the nodal cilia. A host of studies has also...