Circumpolar phylogeography of Vaccinium uliginosum inferred from cpDNA sequences

Abstract

The origin of the arctic flora and the localisation of glacial refugia and postglacial migration routes have been debated for more than 100 years. In this project, we use cpDNA data to infer the phylogeography of Vaccinium uliginosum L ., of which three subspecies have been described: the circumpolar diploid ssp. microphyllum the , circumpolar/circumboreal-lowland tetraploid ssp . uliginosum, and ssp. alpinum, which has been recorded from southern mountains as well as subarctic areas. We have so far sequenced two non-coding cpDNA regions from 67 populations, which revealed 20 polymorphic sites combining into 12 haplotypes. The data were analysed using maximum parsimony. One arctic haplotype was extremely widespread, occurring from Alaska through arctic Canada, Greenland, Svalbard, and northernmost Norway to the Ural Mts. in Russia. This haplotype was closely related to other arctic haplotypes, as well as to haplotypes only found in the Alps and the Pyrenees. Another haplotype was found all over Scandinavia, Scotland, Iceland, and SE Greenland, with a closely related haplotype in Canada (Newfoundland). The latter two haplotypes correspond well with the distribution of the tetraploid ssp. uliginosum, which probably has evolved from arctic-alpine ancestors. Possible refugia areas and migration routes are discussed.