Crested newts (Triturus cristatus superspecies) are a group of closely related species with parapatric distributions that are likely to interbreed where their ranges meet. Coexistence of three species of the complex (Triturus cristatus, T. dobrogicus and T. carnifex) has been recently confirmed in central Europe. In this study we aim to elucidate the distribution of crested newts in contact zones in the Czech Republic and Slovakia, and determine the extent of hybridization and introgression using nuclear (microsatellites and Randomly Amplified Polymorphic DNA, RAPD) and mitochondrial DNA (mtDNA) markers. Nuclear markers reveal hybrid zones between T. cristatus and T. dobrogicus at the foothills of the Carpathians in southern Slovakia, and between T. cristatus and T. carnifex in the southern parts of the Czech Republic. Analysis of mitochondrial cytochrome b sequences reveals T. cristatus and T. dobrogicus-specific haplotypes in contact zones in southern Slovakia. Surprisingly, most T. carnifex and individuals with mixed ancestry between T. carnifex and T. cristatus possess haplotypes specific for T. dobrogicus, most likely as a result of historical mtDNA introgression. Only one T. carnifex-specific haplotype carried by a single specimen is found in the Czech Republic. Our study shows that genetic structure of central European populations of crested newts is complex and influenced by historical and contemporary hybridization.
Overlapping measurements in the length of the genitalia of Leptidea sinapis/reali collected in Slovenia triggered an investigation of a possible natural hybridization between these two well known sibling species of butterflies. Random polymorphic DNA (RAPD) was used to generate species specific markers and sequences of the cytochrome oxidase subunit one gene for determination of the progeny. RAPD's clustering and mitochondrial DNA (mtDNA) phylogeny were congruent with the taxonomic placement of specimens of both species, but slightly incongruent with the results of the analysis of genital morphology. Two specimens with L. reali genitalia measurements, but genetically belonging to L. sinapis, had species specific RAPD markers of both species indicating probable hybrid origin. All the specimens with genitalia of intermediate length were also genetically assigned to L. sinapis indicating a possible one way introgression as predicted from their genitalia morphology. Leptidea sinapis was found predominantly in xerothermic habitats in Slovenia, whereas L. reali was more of a generalist except in the sub-Mediterranean region where it is limited to humid meadows.