Colour Vision Genetics Learned from New World Monkeys in Santa Rosa, Costa Rica

Abstract

By the mid-1980s, it was known that colour vision was polymorphic in New World monkeys due to allelic variation of the L/M opsin gene. However, until the early 2000s, it was unknown whether this polymorphism existed within social groups of wild monkeys, other than mixed-species troops of tamarins. In 2003, I embarked on a collaborative project with Linda Fedigan and colleagues in Santa Rosa National Park. We collected faecal samples from white-faced capuchin monkeys (Cebus capucinus) and black-handed spider monkeys (Ateles geoffroyi) that were individually identified by researchers. The major findings of our genetic studies were (1) the confirmation of the allelic polymorphism of the L/M opsin within social groups of each of the two species, (2) the discovery of a novel spectral tuning mechanism in ateline L/M alleles, (3) population genetic evidence for balancing selection on the L/M opsin alleles in the two species, (4) unequal allele frequencies of L/M opsins and (5) the discovery of hybrid L/M opsins in sympatric howler monkeys. Of equal importance has been the ecological side of our colour vision study. In this chapter I summarize basic knowledge on colour vision and visual opsin genes in primates and then describe the contribution of our studies in Santa Rosa to our understanding of primate colour vision evolution.