Genetic Diversity and Differentiation of the Iranian's Betula pendula Populations by DNA Polymorphisms of Three (CD, DT, K1K2) Chloroplast Genome Regions

Genetic diversity of Betula pendula, which is a medicinal value and endangered species, in small populations remaining in profile of northern Iran including: Marmishoo, Siahmarzkoh, Sangdeh and Shahrestanak, studied by polymorphisms of the three (3800, 1800, 2700 bp) regions of chloroplast DNA and PCR-RFLP technique. These regions named to CD, DT, K1K2, respectively. The percentage of polymorphic loci, expected heterozygosity (He) and Shannon’s information index (I) in four populations, calculated to 24.51%, 0.096 and 0.14, respectively. Analysis of molecular variance (AMOVA), revealed that 66% of total variation was found within populations, while only 34% among populations. Genetic differentiation index (Gst= 0.206) revealed a high differentiation of birch populations to each other. Pair-wise comparison of genetic differentiation showed that, Marmishoo's population by highest level of differentiation from other populations. Assessment of gene flow among populations indicate the occurrence of genetic drift between them (Nm= 0.96). In addition, Mantel test revealed a significant correlation (r=0.77) between genetic and geographical distances. Our results confirmed that the occurrence of genetic drift in birch populations, and the extinction risk of this species. Which emphasize to deployment fast and convenient strategy to it's protect.