Evolutionary Diversification of Visual Opsin Genes in Fish and Primates

Abstract

AbstractAmong vertebrates, fish and primates are highly polymorphic in their color vision. This diversity likely reflects the variability in light environments inhabited by these species. Gene duplications and allelic differentiation of opsin genes play an important role in the evolution of color vision in fish and primates. Studies have shown that gene duplications of opsins have occurred repeatedly during fish evolution, often accompanied by differentiation of spectral sensitivity and ­spatiotemporal expression patterns in the retina, which possibly enabled different color sensitivities between upward and downward vision. Interestingly, a similar regulatory mechanism for the expression of duplicated opsin genes, in which a single regulatory region controls the array of duplicated opsin genes, has evolved independently in fish and primates. However, this regulatory mechanism has resulted in different consequences for fish and primates: different sights by visual angles in fish and trichromatic color vision in primates. New World monkeys have the single-copy but multiallelic M/LWS opsin gene and hence exhibit an extensive intraspecific polymorphism of color vision. Behavioral observations of New World monkeys in the wild have revealed surprising findings, including that dichromatic monkeys perform better catching camouflaged insects than their trichromatic group mates and that these dichromats can be as good as trichromats when foraging for fruits. Interdisciplinary studies that emphasize a study of genes and behaviors will continue to uncover surprising variations of color vision and promote our understanding of the adaptive significance of color vision in evolution.KeywordsColor VisionSpectral TypeWorld MonkeyVisual PigmentOpsin GeneThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.