Most opsin proteins are located in the rods and cones of the eye's retina. But the dissected chick eye had no rods or cones, and its response to light was different than a normal visual response.

Scientists hijacked the human eye to get it to see a brand-new color. It's called 'olo.' Chickens sprouted dino ... photoreceptors in the retina called rods, while daytime vision relies on ...