Firefly genomes illuminate the evolution of beetle bioluminescent systems

Fireflies are one of the best-known bioluminescent organisms, and the reaction mechanism and ecological utility of bioluminescence have been well-studied. Genome assemblies of six species of bioluminescent beetles have recently been published. These studies have focused on the evolution of novelties; luciferase, and the biosynthesis of luciferin and defensive chemicals. For example, clustering of the luciferase gene with acyl-CoA synthetase genes on a chromosome in luminous beetle genomes suggests the involvement of tandem gene duplications and neofunctionalization during the evolution of beetle bioluminescence. Several candidate genes for critical roles in beetle bioluminescence have been identified, but their functional analyses are still ongoing. The establishment of a long-term mass-rearing system and strain will be the key for the post-genome research on bioluminescent beetles. Lastly, the application of contemporary chromosome-scale genome assembly techniques to luminous beetles will help resolve outstanding evolutionary questions, such as how many times bioluminescence evolved in this clade.