Abstract
The intraspecific genetic diversity of the circumpolar Vaccinium uliginosum (Ericaceae) was examined to determine the origin of circumpolar plants that migrated to the Japanese archipelago during the cold periods of the Pleistocene. The high mountains of the Japanese archipelago are among the southernmost limits of distribution of circumpolar plant species. Two noncoding regions of the chloroplast DNA (trnL-trnF and trnS-trnG intergenic spacers) were sequenced to determine the phylogeographic histories of the plants inhabiting five sites in the Japanese mountains and one site on the Kamchatka Peninsula. The sequences were used to extend a previously constructed dataset on global phylogeography, which identified three main lineages: an arctic-alpine lineage, an amphi-Atlantic lineage, and a Beringian lineage. All three cpDNA haplotypes in the mountains of Japan and on the Kamchatka Peninsula belonged to the Beringian lineage. A key finding in this study is that Beringia appears to be the phylogeographic origin of V. uliginosum in the Japanese archipelago. The Beringian refugium hypothesis proposed by Eric Hulten may therefore be applicable to a significant portion of the Japanese alpine flora.
