Molecular variation and population structure in Elymus trachycaulus and comparison with its morphologically similar E. alaskanus

Random amplified polymorphic DNA (RAPD) markers were used to determine the levels and pattern of molecular variation in four populations of Elymus trachycaulus, and to estimate genetic similarity among different populations of E. trachycaulus from British Columbia and the Northwest Territories and one population of Elymus alaskanus from the Northwest Territories. Based on 124 RAPD bands (loci), mean percent polymorphic loci for E. trachycaulus (P_P) was 67.4% (a range 41.2% to 86.3%), and mean gene diversity (H_e) for E. trachycaulus species was 0.23 (range 0.18 to 0.27). The total genetic diversity was 0.32. Differentiation among populations was 31% (F_ST = 0.31) with most of the genetic variation found within populations (69%). This pattern of genetic variation was different from that reported for inbred species in general.The authors are very grateful to Michael Bond for excellent Laboratory assistance, to Dr. Mary Barkworth for her encouragement. This study was supported by a Natural Science and Engineering Research Council (NSERC) discovery grant and by a Saint Marys University Internal grant to G.S.