Nature Rev. Mol. Cell Biol. 6, 462–475 (2005)

On page 472 of the article, in Figure 6, q27 on chromosome 3 should indicate the position of EPHB3, and not EPHB6. In addition, the axons in parts (b) and (c) of Box 2 should be purple, and not blue, to indicate the co-expression of ephrin-As and EphA receptors.