Genetic variation in the Italian crested newt, Triturus carnifex, and the origin of a non-native population north of the Alps

Genetic variation over 40 protein loci and 46 populations representing three taxa of crested newts revealed moderate genetic distances between Triturus carnifex carnifex, T. c. macedonicus and T. cristatus. Two populations from the Geneva Basin (presumed to be introduced) were genetically similar to T. c. carnifex and dissimilar to T. c. macedonicus and T. cristatus, showing that they belong to T. c. carnifex and not to native T. cristatus. A significant pattern of spatial genetic variation was found within T. c. carnifex along a north to south axis, from Croatia to Calabria. The Genevan populations showed highest genetic similarity with T. carnifex from Tuscany, suggesting that the propagule originated from that area. Effects of a population genetic bottleneck associated with the introduction could not be documented. The observed high allelic variation in Genevan T. c. carnifex could not be directly explained by introgression from T. cristatus. Comparisons across the range, including zones of hybridization within the T. cristatus superspecies, indicated that some alleles typical for the Genevan population may represent the so-called `hybrizymes'.