News Release

Ancestral pigments and night vision evolution

Peer-Reviewed Publication

Proceedings of the National Academy of Sciences

Western Tarsier.

image: Western Tarsier. view more 

Credit: Image courtesy of Stephen J. Rossiter.

A study explores how adaptation to low-light niches occurred over the course of vertebrate evolutionary history. The pigment rhodopsin, present in rod cells of the retina, enables vision in low-light conditions, also called scotopic vision, and allows vertebrates to occupy a diverse range of light-level niches. The properties of ancestral rhodopsins, from the base of major vertebrate lineages, are poorly understood. Yang Liu, Stephen Rossiter, Shuyi Zhang, and colleagues reconstructed ancestral rhodopsins from major vertebrate lineages, exposed the reconstructed pigments to light, and measured the pigments' rates of decay. A slow rate of decay or a long half-life implies an extended signaling state and high adaptation to low-light conditions. The authors report that the common ancestor of all vertebrates had a rhodopsin half-life of around 3 minutes, with shifts toward longer half-lives occurring with the rise of bony fishes and tetrapods. Early tetrapods and amniotes were likely nocturnal, although the first mammals may have occupied both nocturnal and dawn/dusk niches. Dinosaurs appear to have evolved from a nocturnal ancestor, whereas the earliest birds were probably adapted to bright light. According to the authors, the results suggest that advanced adaptation to low-light conditions likely occurred during the early evolution of tetrapods.

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Article #19-00481: "Scotopic rod vision in tetrapods arose from multiple early adaptive shifts in the rate of retinal release," by Yang Liu et al.

MEDIA CONTACT: Yang Liu, Shenyang Agricultural University, CHINA; tel: +86 15542500645; e-mail: <yliu@syau.edu.cn>; Stephen Rossiter, Queen Mary University of London, UNITED KINGDOM; tel: +44 2078825096; e-mail: <s.j.rossiter@qmul.ac.uk>


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