Gradient analysis of the chrogenetic structure of lowland and highland scotch pine populations

Gradients of genetic distances (GGDs) between 26 adjacent cenopopulations of Scotch pine (Pinus sylvestris L.) along the transects through the distinct landscape-ecotopic isolation borders were analyzed graphically. The results made it possible to reveal and quantitatively estimate gradients and borders of gene-pool structural patterns in populations of this species in the central part of Northern Eurasia. In lowland areas, the most distinct borders were found between pine populations growing on dry lands and bogs (Pineta sphagnosa) in the forest zone of the Transural region, as well as between the Arakaragaiskii and Amankaragaiskii island pine forests in the steppe zone (Northern Turgai). In highland areas (the Urals and the Carpathians), the greatest GGDs were observed between low-mountain (about 600 m above sea level) and middle-mountain (850–900 m) populations. Analysis of GGDs is a promising gene-geographic method for determining population borders and studying the chorogenetic structure of species.