Several recent studies based on mitochondrial DNA markers suggested a northern refugium for Scots pine somewhere westwards of the southern part of the Ural Mountains. The objective of our study was to assess the mtDNA polymorphism of Scots pine at the Nad7-1 and Nad1-B/C loci with the aim of detecting the location of this northern glacial refugium and the associated post-glacial migration routes. We studied 54 populations densely covering the European part of Russia westwards of the Ural Mountains, but also populations from the Czech Republic, Poland, Sweden, Finland, Scotland, Georgia and eastern Siberia were included. For the Nad1-B/C locus, all our material was monomorphic. Of the total of 474 individuals tested at the Nad7-1 locus, 348 individuals (73 %) possessed the universal haplotype A of 300 bp and 126 individuals (27 %) - the northern haplotype B of 295 bp. Geographical distribution of the Nad7-1 northern B haplotype was not random (SAMOVA, BAPS) forming a consistent cline directed towards north-west of the south-eastern part of European Russia up to the Scandinavia in the north. This provides a stronger support for the south-eastern rather than the central European location of the northern glacial refugium. A possible location of the northern refugium could be at about 300 km south-east of Moscow, where the northern B haplotype occurs in high frequency and Scots pine could possibly survive during the LGM. There also is a possibility for a more southern location of the northern refugium, assuming that such signature was lost during the northward migration or via genetic drift.

Key words: differentiation, glaciation, LGM, Pinus sylvestris, phylogeography, post-glacial colonisation, mtDNA, organellar DNA.