Population genetic analysis of Fagus orientalis with biogeographical notes

The genetic structure of 39 populations of oriental beech (Fagus orientalis) from the territory of Crimea, the Caucasus, Asia Minor, and Alborz was studied based on the polymorphism of microsatellite, or single sequence repeats (SSR). Tests for isolation by distance (IBD) conducted in the GenePop program showed a high correlation of genetic differences and the logarithm of the geographic distance in units of geographic coordinates at the level of 0.91. Interpopulation genetic differentiation of Fagus orientalis (Fst) ranged from 0.01 to 0.67. The putative relationship of the species populations by the area is presented. A possible prochoresis of the ancestors of F. orientalis is reconstructed; probable paths of the formation of the modern area of the species are considered, including the effects of glaciation and volcanism in the Caucasus. Along with refugial populations, examples of Holocene recolonization of the highlands of the Greater Caucasus are given. The observed similarity at the upper boundary of the beech belt in different regions of the Caucasian Isthmus indicates parallelism in the development and establishment of high-mountain populations of the species, or repeated colonizations.