Intraspecific variation and geographic patterns of Fagus orientalis Lipsky chloroplast DNA

CpDNA variation in Iranian beech, Fagus orientalis Lipsky (Fagaceae) was studied in 14 populations distributed throughout the species range in the Hyrcanain zone. Two cpDNA intergenic regions were analyzed: (i) one in the DT region between trnD (tRNA-Asp) and trnT (tRNA-Thr) genes, and (ii) one in the OA region between the orf184 and petA genes. The restriction fragments of the region DT did not show polymorphism among individuals within any population analyzed. However, among individuals within analyzed populations of Asalem region and Neka-1400 population, polymorphism in the restriction fragments of the OA region were found. A total of 3 different chloroplast (cp) haplotypes were scored. The distribution of the cpDNA haplotypes revealed a geographical structure of the genetic differentiation with Gst = %68.7 and Nst = %70.3. The distribution pattern of F. orientalis cpDNA haplotypes may reflect environmental differences and migration history of beech during historical distribution in Tertiary from Asalem (most polymorphic region) to East of Hyrcanian forests.