AMPLIFICATION OF MYOADENYLATE DEAMINASE DURING EVOLUTION - A COMPARATIVE-STUDY

Myoadenylate deaminase activity was measured, by using a specific assa y technique, in a wide range of animal species, including four inverte brates, one cyclostom, 13 chondrosteans, one teleost and one mammal. T he results are discussed considering the known genetic events that hav e lead to the appearance of the higher vertebrates myoadenylate deamin ase molecular form. It is proposed that, during the extensive gene dup lication that occurred in the beginning of vertebrate evolution, genet ic modification of the myoadenylate deaminase molecule took place in a t least two different taxa : the one that evolved to rajiform elasmobr anch fishes and the other to the land vertebrates.