Evidence for two genetic groups within the arctoalpine sedges Carex bicolor All. and C. atrofusca Schkuhr (Cyperaceae)

Abstract

C. bicolor and C. atrofusca are sedge species characteristic for arctoalpine habitats. They have almost circumpolar distributions; they are found in Europe, Northern Asia, and North America, as well as in Middle Asia (C. atrofusca). We hypothesized that certain genetic and morphological differences between populations may be expected across this large area. We tested a set of geographically remote populations of C. bicolor and C. atrofusca. We sequenced a fragment of the plastid matk gene for 15 specimens of C. bicolor and 10 specimens for C. atrofusca from the Asian Russia, and also extracted sequences of this species from GenBank. We found that for both C. bicolor and C. atrofusca, plants from the Arctic and boreal zones of North America and Eurasia had identical matk sequences, while there was certain nucleotide diversity in the mountain ranges of the southern Siberia. Therefore, based on the obtained data we may hypothesize that the mountains of the East Siberia are the center of diversity for some arctoalpine sedge species, and might have served as the ancestral area of the populations colonizing the Arctic.