Searching for and Revealing the System of Pleistocene Refugia for the Species Pinus sylvestris L.

A comparative allozyme analysis of Pinus sylvestris L. populations distributed over the entire species range has been performed to estimate Nei’s minimum genetic distances among eight phylogeographic population groups (PPGs) from the “glacial” zone and 26 populations from the southern “extraglacial” zone. On this basis, the locations of nine main and eight second-order hypothetical Pleistocene refugia (HPRs) for the species have been determined. Using the conditional “refugium investment index,” relative contributions from the gene pools of HPRs to those of PPGs from the glacial zone has been estimated. It is shown that populations of this zone have originated from several refugia. A classification of Pleistocene refugia for P. sylvestris is proposed, which is based on their location within the range and role in the formation of the current gene pool of the species.