Dr. Elizabeth Torres, a new faculty member at California State University, Los Angeles, is studying the molecular evolution of bioluminescence in small marine crustaceans of the ostracode family Cypridinidae. Although bioluminescence is now known in numerous groups of organisms, including bacteria, dinoflagellates, coelenterates, annelids, molluscs, fireflies, and crustaceans, it is hypothesized to have evolved independently in all these groups. Cypridinids produce their own unique forms of the enzyme luciferase and the substrate luciferin, the molecules responsible for bioluminescence. Recent phylogenetic analyses of Cypridinidae, based on molecular and morphological data, suggest that bioluminescence evolved just once in the family (but has been lost or altered in various lineages). To analyze the pattern of mutational changes in the luciferase gene throughout the lineages of cypridinids, gene probes are being constructed, based on the known gene sequences from Vargula hilgendorfii and anticipated from clones in hand of Vargula tsujii. These can be used to survey gene-nucleotide differences across numerous cypridinid species. With several such sequences known across many taxa, one can also begin analyses of conserved motifs and other gene characteristics, to test the hypothesis that luciferases have evolved from oxygenase enzymes, in the various groups of bioluminescent organisms.
