Genetic variation, taxonomy and mountain-hopping of four bipolar Carex species (Cyperaceae) analysed by AFLP fingerprinting

The bipolar sedges Carex canescens, C. echinata, C. lachenalii and C. magellanica (including C. paupercula) were analysed by amplified fragment length polymorphisms (AFLPs). The genetic variation of Carex populations from northern Europe was compared with those from the farthest locations in the Southern Hemisphere (i.e. Australia, New Zealand and Chile). This DNA fingerprinting of 152 plants yielded 223 AFLP bands, which were scored as present/absent and converted to Jaccard's dichotomy coefficients. Unweighted pairgroup methods using arithmetic averages (UPGMA), neighbour-joining (NJ), and principal coordinate analysis (PCA) were performed. We obtained AFLP-based separations of the four Carex species that were in full agreement with previous morphology-based taxonomy. A large number of species-specific bands occurred. Hemisphere-specific bands were not identified, but all analyses showed a clear distinction between populations collected from the Northern and Southern Hemispheres. The results are discussed in relation to the mountain-hopping hypothesis, which is one possible mechanism underlying the bipolar distribution of those species.