The Unlikely Relationship Between a Brittle Star and a Sea Pansy

The presence of similar light-emitting enzymes in the distantly related organisms lends new insight into bioluminescence evolution.

Aggie Mika
Jul 16, 2017

SEA STAR LUMINESCENCE: High sensitivity macrophotography captures a brittle star arm emitting light.JÉRÔME MALLEFET, JÉRÔME DELROISSE

EDITOR'S CHOICE IN EVOLUTIONARY BIOLOGY

The paper
J. Delroisse et al., “A puzzling homology: A brittle star using a putative cnidarian-type luciferase for bioluminescence,” Open Biology, 7:160300, 2017.

Degrees of separation
Although the long-tentacled brittle star (Amphiura filiformis) differs from the stout sea pansy (Renilla) in both appearance and phylogeny, researchers have now demonstrated that they share a similar luciferase—an enzyme that catalyzes the light-producing reaction that results in the invertebrates’ bioluminescence.

Unexpected homology
When an international group of researchers searched the brittle star’s genome and transcriptome for known luciferase sequences, they detected sequences in the echinoderm that were homologous to those of the luciferase of the sea pansy—a cnidarian. The sequences were so similar, in fact, that antibodies specific to the sea pansy luciferase could also...