Genetic diversity of Buxus hyrcana populations in north of Iran using ISSR markers

Precise evaluation of extent and distribution of genetic diversity in rare and endangered species is of particular importance for conserving and utilizing genetic resources. To study inter- and intra-population genetic diversity of three natural populations of boxus (Buxus hyrcana Pojark.) in north of Iran (Bandar Gaz, Nowshahr and Gorgan) ISSR markers were used. Twenty samples per population were randomly selected, their DNA was amplified in PCR reaction using 10 ISSR primers and electrophoretic patterns were obtained. Then, population genetic parameters were calculated based on respective numerical scores. Results showed that there was a desirable genetic variation (34.1%) in the studied populations. However, contribution of intra-population genetic variation in total genetic variation was estimated over than that of inter-population genetic variation (73% vs. 27%). On the basis of Nei`s similarity, a relatively high genetic similarity (74 to 88%) was observed among the populations. The lowest genetic distance (13.2%) was observed between Bandar Gaz`s and Gorgan`s populations and the highest amount (30.1%) was observed between Gorgan`s and Nowshar`s populations. Based on cluster analysis using UPGMA method, populations of Bandr Gaz and Gorgan were grouped together, indicating their higher genetic relatedness and this grouping coincided to geographic distribution. Investigation of Hardy-Winberg genetic equilibrium showed that Bandar Gaz`s population had the highest genetic equilibrium at different loci (~78.9% of loci), while two other populations had a mild equilibrium (58% and 63% of loci in Nowshahr and Gorgan populations, respectively). Gene disequilibrium in the latter populations is probably due to harder endangering forests and losing the hereditary resources of boxus species in the regions. Altogether, on the basis of the results of this research it can be concluded that ISSR markers are efficient and reliable markers for studying genetic diversity and population genetics of Buxus hyrcana species in forests of north of Iran.