成人大片

鈥淥ur research has found that the annulated sea snake possesses four intact copies of the opsin gene SWS1,鈥� said PhD candidate Isaac Rossetto, from the 成人大片鈥檚 School of Biological Sciences who led the study.

鈥淭wo of these genes have the ancestral ultraviolet sensitivity, and two have evolved a new sensitivity to the longer wavelengths that dominate ocean habitats.

鈥淭he earliest snakes lost much of their ability to see colour due to their dim-light burrowing lifestyle.

鈥淗owever, 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 colours sea snakes can see.鈥�

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聽annulated sea snake, a species of venomous snake found in tropical and subtropical regions of Australia and Asia.

The team included scientists from The 成人大片, The University of Plymouth and The Vietnamese Academy of Science and Technology. They published their findings in the journal Genome Biology and Evolution.

Many animals have lost opsins throughout their genealogical history as they鈥檝e adapted to new habitats, but it is very rare to see opsin gains.

鈥淗umans have a similarly expanded sensitivity to colours, while cats and dogs are partially colour-blind much like those early snakes,鈥� said Mr Rossetto.

鈥淚t鈥檚 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.鈥�

鈥淏asically, there鈥檚 only one other case within reptiles at all where we think this has happened.鈥�

Newly gained colour-vision opsins have also been recorded in the semi-aquatic Helicops snake.

Evidence of colour 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 colour vision is more common among the species than first thought.

鈥淲ith a polymorphism, it鈥檚 a bit of a lottery 鈥� only some individuals would have that extended colour sensitivity. But now we know that there are multiple gene copies which have diverged, so colour vision is expected to be seen in all members of these species,鈥� said Mr Rossetto.