Figure 2.

Three steps in the establishment of L-R asymmetry in vertebrates. The three steps include symmetry breaking, patterning, and organogenesis. In the first step, many vertebrates rely on cilia for symmetry breaking, whereas others deploy a cilia-independent, largely unknown mechanism. In the second step, the LPM on the right and left sides undergoes differential patterning as a result of asymmetric Nodal signaling on the left side. In the final step, asymmetric morphogenesis takes place in visceral organs. Modified with permission from Shiratori and Hamada¹⁵⁵⁾ and Yoshiba and Hamada.¹⁵⁶⁾