Natural bioluminescence as a genetic marker for ophiuroid species

Bioluminescence is the emission of visible light by living organisms. This amazing property is used in various research fields such as genetics, molecular biology, chemistry, etc. The aim of this work was to gather evidence that bioluminescence could also be used as a genetic marker in various luminescent species. Previous studies with the brittlestar Amphipholis squamata have shown that bioluminescence is an excellent marker for intraspecific genetic variability. The method, using maximum luminous capabilities induced by KCl 200mM depolarization, presents numerous advantages over other genetic markers (RAPDs, microsatellites, RFLP, etc.) : it is cheaper, faster and easier to use. Since bioluminescence is a frequent phenomenon in brittlestars, the same method was used to compare variability between six different species : Amphipholis squamata, Amphiura filiformis, A. arcystata, Ophiopsila aranea, O. californica and a new species of Amphiodia. Our results show that Amphiodia and both Ophiopsila species could be clearly isolated, each in a separated cluster, according to their luminous capabilities. These differences could be explained by physiological properties. On the other hand, an important intraspecific variability was observed for two species (A. squamata and A. filiformis). We propose that natural bioluminescence is a good marker to study inter- and intraspecific variability, providing useful functional information for physiological and population studies.