In a outstanding evolutionary improvement, a crew of worldwide scientists has found that sea snakes have enhanced their colour imaginative and prescient on account of their transition to brighter and extra colourful marine habitats.
Scientists have found that sea snakes have enhanced their colour imaginative and prescient on account of residing in vibrant marine environments.
“Our research has found that the annulated sea snake possesses four intact copies of the opsin gene SWS1,” said PhD candidate Isaac Rossetto, from the University of Adelaide’s School of Biological Sciences who led the study.
“The earliest snakes lost much of their ability to see color due to their dim-light burrowing lifestyle.
“However, their sea snake descendants now occupy brighter and more spectrally complex marine environments. We believe that recent gene duplications have dramatically expanded the range of colors sea snakes can see.”
The team examined published reference genomes to examine visual opsin genes across five ecologically distinct species of elapid snakes. They looked at the gene data of Hydrophis cyanocinctus, or the annulated sea snake, a species of venomous snake found in tropical and subtropical regions of Australia and Asia.
The team included scientists from The University of Adelaide, The University of Plymouth, and The Vietnamese Academy of Science and Technology. They published their findings in the journal Genome Biology and Evolution.
Hydrophis cyanocinctus. Credit: Parviz Ghezellou
Many animals have lost opsins throughout their genealogical history as they’ve adapted to new habitats, but it is very rare to see opsin gains.
“Humans have a similarly expanded sensitivity to colors, while cats and dogs are partially color-blind much like those early snakes,” said Mr Rossetto.
“It’s quite unique and interesting that these snakes appear to be gaining and diversifying their opsins, when other land-to-sea transitioned animals have done the opposite.”
“Basically, there’s only one other case within reptiles at all where we think this has happened.”
Newly gained color-vision opsins have also been recorded in the semi-aquatic Helicops snake.
Evidence of color vision in Hydrophis snakes was first published in 2020, but this new research shows it is the result of gene duplication rather than gene polymorphism. This means expanded color vision is more common among the species than first thought.
“With a polymorphism, it’s a bit of a lottery – only some individuals would have that extended color sensitivity. But now we know that there are multiple gene copies which have diverged, so color vision is expected to be seen in all members of these species,” said Mr. Rossetto.
Reference: “Functional Duplication of the Short-Wavelength-Sensitive Opsin in Sea Snakes: Evidence for Reexpanded Color Sensitivity Following Ancestral Regression” by Isaac H Rossetto, Kate L Sanders, Bruno F Simões, Nguyen Van Cao and Alastair J Ludington, 12 July 2023, Genome Biology and Evolution.
DOI: 10.1093/gbe/evad107
Funding: Australian Research Council Discovery Project
