Evolution of human colour vision opsins was increasing from 400 to 430. During this time, Ancestral Boreotherian had two long wave length opsins created by gene duplication, with one retaining the absolute max value of 560, equal to the ancestral value. This led to the creation of the modern human long wavelength sensitive, or red opsin. The other short wavelength sensitive opsin decreased its absolute max value to 530 and became the middle wavelength sensitive, or green-sensitive opsin. This occurred through mutations involving S180A, Y277F and T285A. The order that these mutations took place in the ancestral Boreotheria is currently not fully known. It is
Evolution of human colour vision ago and 20 45 million years ago. It eventually reached the current λmax of 430 30 million years ago. It is believed that middle and long wave sensitive pigments appeared after the final stages of short wavelength sensitive opsin pigments evolved, and that trichromatic vision was formed through interprotein epistasis. Scientists believe that the slow rate of evolution of human ancestral vision can also be attributed to slow environmental changes. It has been theorized that -shifts might have been required as human ancestors started to switch from leading nocturnal lifestyles to more diurnal lifestyles. This caused their vision to adjust