Vucić, M., D. Jelić, G. I. V. Klobučar, B. Prkljačić & M. Jelić

Molecular identification of species and hybrids of water frogs (genus Pelophylax) from Lake Skadar, Southeast Adriatic drainages (Amphibia: Ranidae). pp. 147-157 plus Supplementary material.

Abstract. Species composition of Eurasian water frogs, genus Pelophylax, in Lake Skadar (Montenegro) was analysed using mitochondrial (mtDNA) and nuclear (nuDNA) markers. Specimens were characterised at first using mtDNA sequences of NADH dehydrogenase subunit 3 (ND3) gene. Based on their mitochondrial genomes, 49 specimens were determined as Pelophylax kurtmuelleri while 39 specimens were identified as Pelophylax shqipericus. The systematic affiliation was evaluated further using serum albumin intron-1 (SAI-1) nuDNA. The results of SAI-1 analyses confirmed identification of both species but also their hybrids. The SAI-1 variant of P. shqipericus was ~600 nucleotide base pairs longer compared to P. kurtmuelleri. Five specimens contained both variants, indicating their hybrid origin. However, population allotment of hybrids was low, suggesting normal Mendelian inheritance in the interspecific mating of P. kurtmuelleri and P. shqipericus rather than a hybridogenetic mode of reproduction. Mito-nuclear discordance as a result of backcross hybridization was not observed in this study. However, the absence of mito-nuclear discordance is not surprising since backcross specimens were rarely detected in previous research of water frogs from Lake Skadar. This study showed that species composition in Lake Skadar is the same compared to 30 years ago, when a previous study analysed the water frogs using protein electrophoresis.

Key words. Hybridization, indigenous species, NADH dehydrogenase subunit 3, gene serum albumin intron-1, Ranidae.