Amplification of myoadenylate deaminase during evolution. A comparative study.

Myoadenylate deaminase activity was measured, by using a specific assay technique, in a wide range of animal species, including four invertebrates, one cyclostome, 13 chondrosteans, one teleost and one mammal. The results are discussed considering the known genetic events that have lead to the appearance of the higher vertebrates myoadenylate deaminase molecular form. It is proposed that, during the extensive gene duplication that occurred in the beginning of vertebrate evolution, genetic modification of the myoadenylate deaminase molecule took place in at least two different taxa: the one that evolved to rajiform elasmobranch fishes and the other to the land vertebrates.