“The luminous organs which occur only in a few insects, belonging to widely different families and orders, and which are situated in different parts of the body...” -C. Darwin,

The evolution of complex trait is one of the challenging problem in Biology. Bioluminescence is one good example of the novel traits which had puzzled biologists on account the “mode of transition” as Darwin pointed in his book, Origin of Species. Luciferase is one of the key gene to unveil the evolution of bioluminescence. Previous studies suggested that the luciferase gene evolved from an ancestral fatty acyl-CoA synthetase. To understand more deeply, we conducted comparative genome analysis using two fireflies, Aquatica lateralis and Photinus pyrialis, and luminous click beetle, Ignelator luminosus. We analyzed several genes possibly involving in bioluminescence, and found the high multiplicity of them, especially in fatty acyl-CoA synthetase. These results suggest that gene duplication may play a significant role to evolve the functional novelty of enzyme. Based on these megadata, we will discuss an evolutionary scenario of bioluminescence.