THE CHEMICAL MECHANISM AND EVOLUTIONARY DEVELOPMENT OF BEETLE BIOLUMINESCENCE

Bioluminescence, as a phenotype, has many evolutionary origins, and th us is an example of natural reinvention many times over. Although pecu liar, it arises from the same biochemical principles and evolutionary mechanisms as other biochemical reactions. Of these many different bio luminescent systems, that of the luminous beetles is one of the best u nderstood, having been extensively studied for over 50 years. The lumi nescence ensues from oxidation of a molecule unique to luminous beetle s, beetle luciferin, through a catalytic mechanism evolved from ancest ral coenzyme A synthetases. Thus, the character of this bioluminescent reaction is in part a consequence of that evolutionary history. Beetl e bioluminescence is furthermore unusual in having a range of luminesc ent colors found among different beetle species and sometimes even wit hin individual beetles. Structural features of the luciferases are res ponsible for these color differences, although the underlying mechanis m is not yet clear.