Fig. 4.

—The adaptive gene network of the barn owl eye-development genes. The eye-development genes showing adaptive evolution in the barn owl lineage, along with those correlated with the orbit convergence in birds (marked with an asterisk), were inspected for functional roles in ocular structures: lens and cornea (green), eyelid (gray), eyecup (blue), iris (yellow), retina (red), and optic nerve (purple). We determined possible roles of these 25 genes in ocular structures from previously described phenotypes, syndromes, and malfunctions with which they have been associated(table 1). Genes associated with several eye-structures are represented in the circle’s boundaries: pax2 and prox1. Signatures of coevolution among avian eye-development genes are represented in gray lines.