Variability of Nuclear Microsatellite Loci and Population History of the Widespread Siberian fir Abies sibirica and the Tien Shan Endemic Semenov’s fir A. semenovii

High variability of nuclear microsatellite markers determines their utility in describing the population structure, biogeography, and demographic history on species level. We used 17 microsatellite loci to study genetic diversity and historical demography of Siberian fir ( Abies sibirica ), one of the most important tree of Siberian taiga forests and its closely related Central Asian endemic species, Semenov’s fir ( A. semenovii ). Bayesian clustering, performed using the STRUCTURE program, revealed groups of A. sibirica populations, presumably corresponding to areas of colonization from several isolated sources – glacial refugia of taiga woods, located in the major mountain systems of Siberia and the Urals. The data obtained significantly supplemented the results of previous studies based on markers of nuclear, chloroplast and mitochondrial DNA. Taking into account the cluster corresponding to the populations along the Yenisei River, it is assumed that there is a refugium in this area related to the last glacial maximum and not identified on the basis of other data. An analysis of demographic history using Approximating Bayesian Computation (ABC) estimates the origin of the South Ural populations of Siberian fir as a result of migrations from Southern Siberia around 65 000 years ago, assuming a generation in fir of 100 years. In addition, ABC modeling confirmed the more recent origin of the North Ural populations of A. sibirica as a result of migration from the Baikal region and mixing with South Ural populations about 36000 BP. Also, using ABC the time of divergence of A. sibirica and A. semenovii was estimated at about 1.24 Ma and the population size of the latter about 30 times less than that of Siberian fir.