Genetic variability of central-western European pine marten (<i>Martes martes</i>) populations

Recent studies highlighted the potential role of cryptic glacial refugia for temperate taxa in Europe beyond the Mediterranean peninsulas. To further investigate phylogeographic features of the European pine marten (Martes martes) in previously identified cryptic refugia located in central-western Europe, we analysed the hyper-variable diagnostic fragment of the mitochondrial control region in a total of 134 specimens, allowing for reliable comparisons with previous genetic studies of the species. We included samples from eight different European countries in central-western Europe (Belgium, France, Luxembourg and the Netherlands), in south-western Europe (Spain), in north-central Europe (Denmark) and in central Europe (Germany and Poland). The sequences collapsed in 17 haplotypes, which allowed us to determine the genetic composition of the pine marten populations throughout central-western Europe. Overall, our results showed that the population genetic variation, estimated by the standardised haplotype diversity, was high (0.400 a parts per thousand currency signaEuro parts per thousand Hs a parts per thousand currency signaEuro parts per thousand 0.762), and it was considerably higher in Germany (0.762) and the Netherlands (0.722) compared to the other countries. The nucleotide diversity was relatively low (0.002 a parts per thousand currency signaEuro parts per thousand pi a parts per thousand currency signaEuro parts per thousand 0.016) even in Germany and the Netherlands (0.016 and 0.014, respectively), suggesting relatively small, long-term effective population sizes or severe bottlenecks. Out of the 17 haplotypes found in our study area, 13 were unique and limited to a single country: one in Denmark, one in Spain, four in Poland and seven in the Netherlands. The pairwise genetic distance ranged from 0.001 to 0.032 and did not show any evident correlation with the geographic distances between the populations. A genealogical relationship network was constructed, which provided evidence for a recent origin of many of the unique haplotypes. Approximately 82 % of the samples analysed in this study belonged to haplotypes grouped into a previously identified central-northern European phylogroup of the species. Our results support previous findings, indicating low contribution of southern refugial populations to the postglacial recolonization of central-western Europe and a predominant contribution of pine marten populations that survived the Last Glacial Maxima in cryptic northern refugia.