Phylogenetic relationships of echinoderms deduced from kinetic similarity of glucose-6-phosphate dehydrogenase

Abstract

1. 1. The phylogenetic relationships among four classes of echinoderms (Asteroidea, Echinoidea, Ophiuroidea and Holothuroidea) have been much disputed among many zoologists and remain unclear. In order to elucidate the phylogenetic relationships, the kinetic properties of glucose-6-phosphate dehydrogenases (G6PDs) purified from four echinoderm groups were compared with each other and the kinetic similarities between the enzymes were estimated. 2. 2. The biochemical dendrogram for four echinoderm groups constructed from the kinetic similarities demonstrated the following: asteroids and holothurians are the most closely related to each other, and more recent, groups. Ophiuroids are more closely related to the cluster consisting of asteroids and holothurians than to echinoids. Echinoids are the most distant group of the four echinoderms and anchestral forms. 3. 3. The biochemical results were discussed through detailed comparison with otehr data, and the evolutionary process of echinoderms was speculated from the biochemical dendrogram and non-molecular evidence.