Meeting Abstract
How new traits originate is a central question in evolutionary biology, but the molecular changes that lead to evolutionary novelty are often difficult to determine. Bioluminescence is a novel trait with a clear genetic basis, and within ostracods, is used for anti-predator displays and complex mating signals. We aim to identify the molecular changes that gave rise to bioluminescence in cypridinid ostracods. To address the origin of molecular function in bioluminescence, we first obtained sequences similar to known luciferases from Illumina transcriptomes of multiple luminescent and non-luminescent species. We characterized luciferase function from different species by expressing the proteins in cell culture and performing light reaction assays. To investigate the molecular origins of luciferase, we used hidden Markov models of the von Willebrand factor type D (VWD) protein domain to find luciferase-like genes and assembled gene trees. From these, we chose two other candidates, named soroluciferase(sluc) and dual-VWD-α (2VWD-α), to test for catalytic ability. Assay results indicate differences in enzyme activity between luciferases of different species, and between sluc and 2VWD-α. We hypothesize that the differential activity between luciferases is correlated with the species’ differences in bioluminescent mating signals due to differences in enzyme kinetics. Together, these analyses support the origin of luciferase via VWD domain fusion and duplication.
