1 Citation 183 Views 16 Downloads
Multiple visual pigments, prerequisites for color vision, are found in
arthropods, but the evolutionary origin of their diversity remains
obscure. In this study, we explore the opsin genes in five distantly
related species of Onychophora, using deep transcriptome sequencing and
screening approaches. Surprisingly, our data reveal the presence of only
one opsin gene (onychopsin) in each onychophoran species, and our
behavioral experiments indicate a maximum sensitivity of onychopsin to
blue–green light. In our phylogenetic analyses, the onychopsins represent
the sister group to the monophyletic clade of visual r-opsins of
arthropods. These results concur with phylogenomic support for the
sister-group status of the Onychophora and Arthropoda and provide evidence
for monochromatic vision in velvet worms and in the last common ancestor
of Onychophora and Arthropoda. We conclude that the diversification of
visual pigments and color vision evolved in arthropods, along with the
evolution of compound eyes—one of the most sophisticated visual systems
known.
183 views reported since publication in 2021.