Fig. 2
From: Widespread nocturnality of living birds stemming from their common ancestor
Positively selected genes mapped onto the phototransduction pathway. Only the positively selected genes found in the common ancestor of extant birds (red), ancestral Carinatae (green), falcons (orange) and owls (violet) are shown. For convenience, both the genes involved in the rod phototransduction pathway (according to KEGG pathway map 04744) and the cone phototransduction pathway are shown. The genes that are involved in the phototransduction pathway of rods, cones and both are shown as dark rectangles, white rectangles and gray rectangles, respectively [12, 13]. *Represents two lost rod-expressed genes, GNGT1 and PDE6A, in both reptiles and birds based on previous studies [7, 9]