A clear molecular view of how human color vision evolved

Many genetic mutations in visual pigments, spread over millions of years, were required for humans to evolve from a primitive mammal with a dim, shadowy view of the world into a greater ape able to see all the colors in a rainbow. Now, after more than two decades of painstaking research, scientists have finished a detailed and complete picture of the evolution of human color vision. The process for how humans switched from ultraviolet (UV) vision to violet vision, or the ability to see blue light. Five classes of opsin genes encode visual pigments for dim-light and color vision. Bits and pieces of the opsin genes change and vision adapts as the environment of a species changes.Around 90 million years ago, our primitive mammalian ancestors were nocturnal and had UV-sensitive and red-sensitive color, giving them a bi-chromatic view of the world. By around 30 million years ago, our ancestors had evolved four classes of opsin genes, giving them the ability to see the full-color spectrum of visible light, except for UV. Gorillas and chimpanzees have human color vision. Just as an animal’s external environment drives natural selection, so do changes in the animal’s molecular environment.