Bright red fluorescence in the larvae of Acropora millepora coral correlates with the activation of a diapause-like state that may aid in conserving energy and tolerating heat and other stressors during a long dispersal to novel habitats.
[3][28] Reconstruction experiments suggest the original fluorescent protein was green, and had a simple beta-barrel shape with a chromophore hidden inside.
Different colors of green fluorescent proteins (GFP), yellow, red, cyan, and amber, are determined by variations in chromophore structure.
New fluorescent proteins evolved through gene duplication and accumulation of multiple mutations which gradually changed autocatalytic functions and final chromophore structure.
[17] Two species of catsharks, Cephaloscyllium ventriosum, endemic to the eastern Pacific, and Scyliorhinus retifer, from the western Atlantic, fluoresce by a different mechanism.
[18] The fluorescence is produced by brominated tryptophan-kynurenine metabolites, small aromatic compounds present in the lighter-colored regions of skin on the fish.