Wirins are members of a widely distributed family of two- and three-Ig domain molecules that mediate axonal guidance, synapse targeting, and other neuronal wiring-related functions. Beginning from a single ancestral Wirin gene in the last common ancestor of Bilateria, numerous gene duplications produced the heterophilic Dprs and DIPs in protostomes, along with two other subfamilies that diversified independently across protostome phyla. In deuterostomes, the ancestral Wirin evolved into the IgLON subfamily of neuronal receptors.(Adapted from
FBrf0245249.)