Heinze B.  

Populus tremula in Siberia: a continantal divide along Lake Baikal

Investigations of aspen (Populus tremula) phylogeography were continued in Europe and Northern Eurasia. We are investigating variation in chloroplast DNA in order to reconstruct the evolution of the chloroplast DNA molecule, and to make inferences on any shifts of the distribution ranges of the species during the last glaciations, i.e. post-glacial re-colonization. Five regions in the chloroplast have been identified as polymorphic in the species in Europe. Surprisingly, Russia and Siberia seem to be dominated by the same, or by very similar, chloroplast genetic variants (haplotypes) as is Europe. While the different haplotypes seem to vary in frequency in a gradual way across most of this vast land mass (from Scotland to Kransnoyarsk), a few samples from east of Lake Baikal break this pattern. There, a new set of haplotypes with strong differentiation appears. This suggests also a deep genetic rift. DNA data from next generation sequencing experiments support this assumption. In this context, the apparent phylogeographic patterns are discussed with a view to the floristic regions in Asia in general, similar examples from other plant species, the Quaternary glaciations in this region, and possible taxonomic consequences.

Abstracts file: Heinze.doc

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