The gene for blue cone opsin is located on a separate chromosome while, in primates, the red and green genes are found together on the X chromosome. We have color vision as a mechanism to increase our visual discrimination, as a means to increase contrast. One theory holds that color is a secondary development arising from the relentless pursuit of high acuity which finished with the evolutionary development of the primate midget system. This retinal circuit has reached the ultimate precision with one cone connected to one midget bipolar cell which, in turn, is connected to one midget ganglion cell. This circuit then is color coded because it is connected to only one cone.
Color provides an extra variable by which to discriminate detail in our richly textured world.
It lends immeasurably to our aesthetic enjoyment but presumably color perception also enhanced our survival rate by improving the performance of the human visual system.