MOLECULAR PHYLOGENY OF BONY FISHES, BASED ON THE AMINO-ACID-SEQUENCE OF THE GROWTH-HORMONE

Bony fishes (Osteichthyes) comprise over 22,000 species, about half of all vertebrate species. In order to investigate the phylogenetic rela tionships within this vertebrate class, we have studied the only prote in whose primary structure is known in a rather large (27) number of f ish species belonging to seven orders-the growth hormone. The phylogen y obtained using the maximum parsimony method based on amino acid sequ ences represents the first molecular phylogeny of teleostean fishes ba sed on an extensive set of data. This phylogeny agrees remarkably well with the generally accepted phylogeny based on morphological characte rs and paleontological data.