'Agouti' is a family of genes previously identified in humans and the first two members are responsible for skin and hair color. Identified by Vanderbilt scientists, AgRP2 the newest member of the family, exclusively found in bony fishes and is claimed to be responsible for the ability of fish to rapidly change color!



Bony fishes have a hormone called Melanin Concentrating Hormone (MCH) that is responsible for lightening and darkening of skin color in response to the surroundings. AgRP2 influences two precursors of this hormone, thereby determining the skin tone of the fish. In the context of fish-habitats, this is a life-saving gift for the fish to become instantly invisible/less-visible in the eyes of the prey.

AgRP (Agouti related protein), the related member of the same family does few things, eventually increasing hunger.  AgRP2 was identified in the Pineal gland, which controls circadian rhythms and so initially thought to be responsible for controlling hunger diurnally. In other words this was attributed to be the reason why fishes feel hungry at certain times of the day and not at other times.

But detailed investigations showed that being in Pineal gland, AgRP2 helps change color of the body in response to the light in the background.

Can we use this discovery to create a system where we can make the object completely light-skinned so that it is invisible?? It is might be a fantasy now, but who knows, it might  be closer to reality than we thought...

Original reports here and here.