MYOSIN POLYMORPHISM IN URODELAN AMPHIBIAN DORSAL SKELETAL-MUSCLE

1. Myosin isoforms were analyzed in the dorsal skeletal muscle of four urodelan amphibian species using a modified pyrophosphate gel electrophoresis which allowed better discrimination than classical methods. 2. The three fast and the intermediate isomyosins were characterized by a specific heavy chain, respectively HCf and HCi, associated with different combinations of the fast light chains LC1f, LC2f and LC3f. 3. Slow myosin was characterized by one (P. waltlii, T. palmatus, S. maculata) or two (T. alpestris) isoforms, combining a specific slow myosin heavy chain (HCs) with slow light chains only in the case of P. waltlii, or with slow and fast light chains in the other species.