COLOUR-changing frog cells could be used to detect performance-enhancing
drugs and leave cheating athletes red-faced. Sensors based on the cells can pick
up traces of drugs in body fluids, and could even detect new drugs that other
methods fail to pick up.
Some frogs, such as the African clawed frog (Xenopus laevis), change
colour to cope with sunlight and heat and also to improve their camouflage. They
do this by activating cells in their skin that contain granules of melanin, the
dark brown pigment.
These colour-changing cells, called melanophores, are normally dark but can
be triggered by a particular hormone…
