In this thesis we analysed the populations of Oriental beech and European beech from various localities in Asia and Europe. For analyses we used nuclear microsatelittes. We isolated DNA and prepared PCR reactions with microsatellite markers. We analysed 510 individuals from 33 populations. The PCR method was used. The genotypes were evaluated by using GeneMapper program. Genetic variability and genetic differentiation between analysed populations of beech waere evaluated. To compare and to confirm the results of the research the comparison with the other sources dealing with the same issues was applied.