Genetic Diversity of Color Vision in Primates

In this chapter we review the various genetic systems of color vision in primates, the origins and evolution of these systems, and the critical amino acid residues responsible for spectral sensitivity differences among primate photopigments (opsins). Much progress has been made on these topics in recent years, thanks to the application of molecular and biochemical techniques as well as the use of traditional approaches to color vision research. The progress has led to the revelation of some misconceptions and to several changes of view. We also discuss the interactions between lifestyle (nocturnal or diurnal) and color vision system, and the role of natural selection in the evolution of color vision in primates. Further, we review evidence of frequent gene conversion between X-linked opsin genes or alleles and describe how gene conversion has made it extremely difficult to infer the evolutionary history of the color vision systems in higher primates.