Approaches for Studying <i>Pelophylax esculentus </i>Complex
European water frog complex (Pelophylax esculentus) represents unique and adequate system for analysis of the interspecies hybridization and of the mechanisms allowing interspecies hybrids to survive and reproduce. Difficulties in water frog species investigation includes high polymorphism of morphological features in parental species and hybrid forms. Moreover polyploid hybrid forms that exist in nature population systems make morphological recognition impossible. Since phenomenon of interspecies hybridization and hybrids reproduction was discovered, researchers faced difficulties connected with precise identification of all individuals. In this review we describe biochemical, cytogenetic and molecular approaches that were commonly used for frogs identification and analysis of genomes transmitted in gametes of hybrids. Moreover we stress advantages and disadvantages of different approaches. Presented methods can be used for analysis of other interspecies hybrid complexes including fishes, amphibians and reptilians. English translation of the paper published in Russian Journal of Genetics, 2017, Vol. 53, No. 8, is available ONLINE by subscription from: http://www.springer.com/, http://link.springer.com/journal/11177