The colours indicate the intensity of
photon accumulation from low (dark blue) to high (yellow) levels. (a) Two weeks after DNA
injection there is a strong light emission detectable in all fish at the site of injection, whereas
(b) luciferin injection into untreated control fish did not result in detectable light emission.
Emission from a single fish is shown after 1 (c), 6 (d) and 24 (e) months.