Limnological Institute, Russian Academy of Science, Siberian Branch, Ulan-Batorskaya ul., 3, Irkutsk 664033, Russia

Abstract

Comparative analysis of nucleotide sequences of gene 18S of ribosome RNA was carried out. The results show that the genetic sequences of the given locus could be used as a molecular marker to identify the species of planaria irrespective of onthogenetic stage. The articles deals with problem of specific determination of cocoons of Baikal planaria from the stomach of Baikal black grayling using comparative analysis of nucleotide sequences of ribosome RNA fragments with known sequences determined earlier for Baikal planaria. The cocoons belongs to two species of Rimacephalus. The authors discuss also the importance of feeding relationships of planaria and benthophage fish to investigate the biotic factors that influence the evolution of Baikal planaria.