Each opsin is a G-protein-coupled receptor clutching a copy of the molecule retinal[22], a light-sensitive molecule that is heavily recycled, but in vertebrates ultimately manufactured from the carotenes, originally photosynthetic molecules inside plants. You may know it as Vitamin A. Thus, in a way, vertebrate vision is co-opted from plant photosynthesis.
I thought this was an evolutionary claim, but it’s a nutritional one: That the individual retinal molecules in my eyes used to be carotenoid molecules in plants on farms in my lifetime. (But in fact a lot of them were synthesized in factories producing dietary supplements.)
I thought this was an evolutionary claim, but it’s a nutritional one: That the individual retinal molecules in my eyes used to be carotenoid molecules in plants on farms in my lifetime. (But in fact a lot of them were synthesized in factories producing dietary supplements.)