Genetic Variation in Populations of the Arctic Perennial Pedicularis dasyantha (Scrophulariaceae), on Svalbard, Norway

Abstract

JSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, and build upon a wide range of content in a trusted digital archive. We use information technology and tools to increase productivity and facilitate new forms of scholarship. For more information about JSTOR, please contact support@jstor.org.Isozyme variability was examined in 13 geographically isolated populations of the endemic arctic hairy lousewort (Pedicularis dasyantha) in the Svalbard Archipelago, 800 N latitude, Norway. Of the 23 enzyme systems screened on five buffer systems 18 were interpretable. Of the 31 reliable loci, only 6-phosphogluconate dehydrogenase (6-Pgd), was polymorphic. However, no heterozygotes were detected. Frequencies for allele 1 among the populations varied from 1.00 in the north to 0.00 in the south and 0.53 in the central "overlap" region. At the species level the mean number of alleles per locus (A) was 1.03. Percentage of polymorphic loci (P) was 3%. Expected heterozygosity (He) was 0.016. At the population level the mean number of alleles per locus was 1.01, and 1.1% of the loci were polymorphic. He was 0.004. These values are low compared to endemic, widespread, selfing, and outcrossed species. Flower color morphs were distinct. They varied within and among the 13 populations. The frequency of color morphs coincided with allele frequencies of 6-PGD: allele 1 was found in dark purple morphs, and allele 2 was found in light morphs. This species shows more isozyme genetic variability than the five other species reported in the genus but generally less variation than other species with limited regional distributions. Low-level genetic variation in this diploid species may be a result of colonization events coupled with genetic drift, founder effects, and strong natural selection. Additional factors include the self-compatible reproductive system and the long-lived perennial habit.

Isozyme variability amongElymusspecies indigenous to the Tibetan and Inner Mongolian Plateaus

“…In self-pollinating species, there is often a significant level of restrictive genetic diversity (Odasz and Savolainen 1996). In self-pollinating species, there is often a significant level of restrictive genetic diversity (Odasz and Savolainen 1996).…”

Local Adaptation, Resistance, and Virulence in a Hemiparasitic Plant-Host Plant Interaction

“…Estimates of gene flow in hemiparasitic plants vary substantially depending on species and the geographic context in which they have been estimated. In the arctic perennial hemiparasite, Pedicularis palustris, gene flow (Nm) among 13 populations on Svalbard was 0.098, that is, gene flow among the populations was extremely low (Odasz and Savolainen 1996). In contrast, in the parasitic weed Striga hermonthica, gene flow (Nm) was 3.42 among three African populations in Sudan and Burkina Faso (calculated from Bharathalakshmi and Musselman 1990).…”

Variation in the Festuca brachyphylla (Poaceae) complex in Svalbard, elucidated by chromosome numbers and isozymes

“…During species dispersion, most of the variation is retained in the source area, because the new colonies are recruited mainly from the marginal parts of the main distribution area. This may lead to consecutive founder events along the migration front, and to genetic depauperation in the new colonies (Barrett & Kohn, 1991), as also postulated for other Svalbard species (Odasz & Savolainen, 1996). Autogamy and ecological cleistogamy has been proved in Russian R baffinensis and R brachyphylla (Levkovsky, Tikhmenev & Levkovsky, 1981).…”