Mitochondrial DNA in Siberian conifers indicates multiple postglacial colonization centers

Abstract

The geographic variation of the mitochondrial DNA in Siberian fir (Abies sibirica Ledeb.) was studied using the newly developed markers and compared with the phylogeographic pattern of another previously studied Siberian conifer, Siberian larch (Larix sibirica Ledeb.). Similar to Siberian larch, the distribution of mtDNA haplotypes in Siberian fir revealed clear differentiation among distinct geographic regions of southern Siberia and the Urals, likely indicating postglacial recolonization from several sources. The northern part of the range of both species was genetically homogeneous, which is probably due to its recent colonization from one of the glacial refugia. This conclusion is in agreement with published pollen and macrofossil data in Siberian fir and with the reconstruction of environmental niches indicating a dramatic reduction of the range and a likely survival of fir in certain southern areas during the Last Glacial Maximum (LGM), 21 thousand years ago. Although the modeling of the Siberian larch ecological niche reconstructed a shift of the range to the south at that period, the paleontological data indicated the presence of this species in most areas of the current range during LGM, which corresponds to the results of a previous historical demographic study suggesting that the population expansion preceding the LGM.