Purine-nucleoside phosphorylase expression in Eleutherodactylus and Leptodactylus frogs.

Purine-nucleoside phosphorylase expression as ascertained electrophoretically is discussed for seven species of Eleutherodactylus and one species of Leptodactylus frogs from Costa Rica. Eleutherodactylus angelicus, E. bransfordii, and E. podiciferus exhibit intraspecific variation unlike the samples of the other five species. In E. angelicus, heterozygotes form a four-banded pattern on starch gels consistent with a trimeric enzyme structure. Heterozygotes of E. bransfordii and E. podiciferus are characterized by a two-banded pattern as the heterotrimeric isozymes are apparently not expressed. Such differences in gene expression are discussed in terms of their potential phylogenetic and systematic application and significance.