Impacts of Genomic and Lighting Environments on Guppy Color Vision

Guppies are one of the best known examples of sexual selection in that females prefer to mate with more colorful males. This raises questions of how do guppies see color and why is color so important to them. Color vision is mediated by transmembrane proteins in the retina called opsins. The peak spectral sensitivity of an opsin is a function of its genetic sequence. Understanding how guppies see and perceive color requires knowing the genetic sequence of the opsins that make up their opsin repertoire in addition to how they use that repertoire. The opsin loci of guppies and 15 other species in the Poeciliidae family were sequenced. High gene conversion activity was found to occur between two long-wavelength sensitive loci throughout the Poeciliidae family. This is most likely due to the genomic environment of these genes, which occur in an inverted orientation within a tandem array of multiple homologous genes. The extent to which the lighting environment influences expression profiles was determined by comparing the light environment and the opsin gene expression of guppies collected simultaneously from natural populations. Understanding the visual system of guppies will allow future work to investigate the mechanisms of choice that result in sexual selection.