Genetic diversity and population structure of Brachythecium rivulare Schimp. (Brachytheciaceae) from Foping Nature Reserve, Shaanxi, China, detected by RAPD markers

摘要

The random amplified polymorphic DNA (RAPD) technique was applied to assess genetic diversity and population structure of Brachythecium rivulare Schimp. (Brachytheciaceae) from Foping Nature Reserve (Qinling Mountain, China). Sixty individuals from five populations along an elevational gradient were investigated by RAPD profiles. Of the 61 primers screened, 12 primers amplified clear and reproducible bands. Using these primers, 122 discernible bands were generated with 82 (67.2%) being polymorphic. The results revealed a high level of genetic variation (percentage of polymorphic loci ranged from 53.28% to 63.11%; mean expected heterozygosity per locus ranged from 0.2024 to 0.2431; Shannon diversity index ranged from 0.3011 to 0.3582; genetic identity ranged from 0.8626 to 0.9395, with a mean of 0.9118; genetic distances ranged from 0.0624 to 0.1478, with a mean of 0.1008). Analysis of molecular variance showed that a large proportion of genetic variation (91.20%) resided within populations, whereas only 8.80% resided among populations. The results also show no significant correlation between genetic distance and elevational gradient among these five populations.