Genetic differentiation of adjacent populations of Scots pine Pinus sylvestris L. from different ecotopes

The genetic structure of two adjacent populations of Scots pine from different ecotopes at a small gradient of ecological changes was studied at 22 loci by allozyme analysis using electrophoresis in polyacrylamide gel. The significant difference between some characteristics of genetic variability (A, P-95 and P-99, and h(mu)) closely related to the proportion of rare alleles in a gene pool of populations was established, whereas heterozygosity and Wright's fixation index were only slightly different. The genetic distance calculated at 19 polymorphic loci was 0.017, which is more than two times higher than that presented in the literature for neighboring populations. The data obtained indicate that even a slight gradient of natural ecological changes leads to the appearance of a genetic barrier between adjacent populations of Pinus sylvestris L.