[Science] Some deep-sea fish have evolved souped-up colour night vision – AI

Stylephorus chordatus is one of several species with extra eye pigment genesSolvin Zankl/naturepl.com By Yvaine YeFish living in the deep ocean have evolved highly-sensitive eyes that can see a range of colour hues in the near-darkness. “It’s a big surprise,” says Zuzana Musilova at the University of Basel in Switzerland. “They have more sensitive eyes and can see way better than humans in lower light.” Musilova and her colleagues collected DNA from 26 species of fish that live more than 200 metres below sea-level. Analysing this DNA, the team found that six species carried additional genes for rod opsin – the light-sensitive protein that enables the retina’s rod cells to detect light. Advertisement Vertebrate animals use rod opsin to detect light in dim environments, but most species – including humans – only have one rod opsin gene. However, adult silver spiny fins (Diretmus argenteus) – a flat fish that lives at depths down to 2,000 meters— has 38 of them. Explore the deep ocean: Ocean explorer Jon Copley will be at New Scientist Live in London this October The team translated these genes into proteins in a dish and shone lights of different wavelengths onto them, to see how they’d respond. They found that that these opsins detect a wide range of colours, and are especially sensitive to green and blue light. “We believe they can detect more shades of blue and green than us,” Musilova says. Musilova says having highly sensitive eyes may be useful for detecting the glowing bioluminescence emitted by many deep-sea creatures. These bioluminescent lights are mostly blue and green in colour. Being able to tell colours apart could help fish distinguish whether a flash comes a predator or prey, Musilova says. Journal reference: Science, DOI: 10.1126/science.aav4632 Read more: Eye of the beholder: How colour vision made us human More on these topics: genetics oceans evolution fish vision