Inter-simple sequence repeat (ISSR) and morphological variation in the western North American range of Chrysosplenium tetrandrum (Saxifragaceae)

• Published in: Botany
• Main Authors: Levsen, Nicholas D., Mort, Mark E.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Canadian Science Publishing 2009
• Subjects: Plant Science; Ecology; Ecology, Evolution, Behavior and Systematics; Arctic; Alaska; Beringia
• Online Access: http://dx.doi.org/10.1139/b09-038; http://www.nrcresearchpress.com/doi/full-xml/10.1139/B09-038; http://www.nrcresearchpress.com/doi/pdf/10.1139/B09-038

The herbaceous perennial Chrysosplenium tetrandrum (Lund ex Malmgr.) Th. Fr. (Saxifragaceae) is a self-pollinating, circumpolar species with a broad latitudinal distribution and a disjunct North American range. The southernmost populations are isolated in the Rocky Mountains of Colorado and Montana, distantly separated from elements of the main range, which is largely coincident with known glacial refugia (e.g., Beringia) and recently deglaciated regions. We employed analyses of inter-simple sequence repeats (ISSRs) and morphology to determine patterns of variation within the western North American range of C. tetrandrum and test hypotheses of glacial population history and reproductive strategy. Analyses revealed very low estimates of range-wide genetic differentiation (θ II = 0.085) and diversity (H S = 0.077, H T = 0.084), which are similar to levels found in other arctic plant species and have been primarily attributed to recent population establishment. Low levels of genetic differentiation among populations of Alaska (θ II = 0.072), British Columbia (θ II = 0.088), and Washington (θ II = 0.058) suggest recent bottleneck or range expansion events. Both the Colorado and Alaska regions showed strong differentiation from each of the other regions, suggesting long-term isolation. The non-association between morphological and genetic variation indicates the effects of phenotypic plasticity or sexual reproduction.