Loci that encode the lactate dehydrogenase in 23 species of fish belonging to the orders Cypriniformes, Siluriformes and Perciformes: Adaptative features

Abstract

1. 1. Electrophoretic analyses of the lactate dehydrogenase isozyme patterns of 23 species of tropical fishes belonging to the orders Cypriniformes, Siluriformes and Perciformes indicates that at least two LDH loci—Ldh-A and Ldh-B are active. In the Perciformes species, in addition to these loci, the Ldh-C is also present, and restricted in its expression to the eye and brain. 2. 2. Genetic variants were detected in the Ldh-A and Ldh-B loci of Leporinus friderici and in the Ldh-B locus of Schizodon borelli Cypriniformes. 3. 3. An increase in the occurrence of the Ldh-BB′ and Ldh-B′B′ allotypes of Leporinus friderici was observed along the successive collects that started in 1980. This change in phenotypic frequency suggests that this polymorphism could be related to environmental conditions.