[Phylogeny of amphibia based on comparison of conserved segments of the 28S rRNA sequence].

The sequences of two regions flanking the 5'D1 domain of 28S rRNA of 13 vertebrate species were determined by direct rRNA sequencing through reverse transcriptase extension of DNA primers. Comparative treatment of these new data and previously reported rRNA sequences was undertaken with special reference to phylogenetic affinity of Amphibia by using some programs of Felsenstein's PHYLIP 3.3 package. The results obtained suggest that Amphibia is rather a biphyletic than a monophyletic group, and that birds and mammals are the closest relevant. These data were compared with those obtained on Vertebrata by using an analogous comparative analysis of 18S rRNA sequences.