Mitochondrial DNA variation in European populations of Silurus glanis

Mitochondrial DNA diversity of 13 wild Silurus glanis populations (covering the entire range of the species) and eight hatchery populations was investigated. PCR-RFLP analysis of four regions of mitochondrial DNA (cytochrome b, control region, ND-5/6) was used. Nineteen haplotypes were found. Thirteen of them were private. The proportion of total genetic diversity attributable to population differentiation was almost 80%. Despite the existence of significant differentiation between populations for mtDNA variation, no consistent pattern of geographic structuring was revealed and nucleotide divergence among S. glanis populations was low. These phenomena are discussed with regard to the impact of glaciation events. The domesticated stocks show less genetic diversity than natural ones, possibly due to their mode of management. Analysis of three European catfish species S. glanis, S. aristotelis and Silurus triostegus (sampled in the Euphrates river) revealed several endonucleases which produced restriction phenotypes diagnostic for the three species.