Abstract: In this study, 15 ISSR primers were used to reveal the genetic diversity and genetic structure of 17 Clintonia udensis populations. The results showed that a relatively high genetic diversity existed in C. udensis, with the percentage of
polymorphic bands ( PPB) from 11.90% to 59.52% at population level ranged , and 98.8% at species level. Moreover, a high level of genetic differentiation among populations was detected based on Shannon′s information index ( 0.6903 ), gene differentiation index GST (0.6944 ), and AMOVA analysis ( 81.47% ) ( P < 0.003 ). The variation of genetic distances among populations ranged from 0.1871 to 0.6632 (with an average of 0.3838), which was higher than that among intraspecies populations (0.05). The gene flow among populations ( Nm=0.2200) was much lower than that of the widespread
species ( Nm = 1 . 881) . In addition , there was no significant correlation between genetic distance and geographical distance among the population studied ( r = 0.029, P = 0.3196). The biological characteristics of this species, limited gene flow and genetic drift might account for the existence of relatively high inter-populational genetic variation . The high level of genetic diversity was probably related with its wide geographical distribution and its evolutionary history .

Key words: Clintonia udensis