Absence of the luciferase gene in the genome of the kleptoprotein bioluminescent fish Parapriacanthus ransonneti.

The metabolic and physiological functions of the living organisms are primarily governed by enzymes encoded within their own genomes. An exception to this doctrine is the phenomenon of kleptobiology, where individuals sequester and use functional modules from their prey. The fish Parapriacanthus ransonneti possesses a luciferase that catalyzes a light-emitting reaction in its light organs. Intriguingly, the protein sequence of this luciferase is identical to that of the ostracod-derived luciferase. We recently demonstrated that the fish sequesters and retains the luciferase from the luminous prey, leading to the hypothesis that the fish does not have a gene encoding the luciferase. To test this hypothesis, here, we produced a high-quality draft genome of P. ransonneti. The assembled size of 625 Mbp closely matches the experimentally estimated genome size of 613 Mbp, and we constructed a gene model with a high BUSCO score. Our search within this gene model did not detect any ostracod-type luciferase genes. Expanding our search to include the entire assembled genome, raw reads, and the transcriptome also supported the absence of the luciferase genes. These results suggest that P. ransonneti lacks the luciferase gene, supporting our previous discovery that it utilizes stolen proteins for bioluminescence.