Twelve populations of Juniperus communis L. were sampled from throughout the arctic, worldwide and DNA fingerprinting (RAPDs, Random Amplified Polymorphic DNAs) was performed. Based on 152 RAPD bands, all of the populations ( J. communis var. depressa Pursh and J. communis var. megistocarpa Fern. and St. John) from the western hemisphere formed one group and all of the populations of the eastern hemisphere (including Greenland and Iceland), formed another group that included J. communis var. communis and J. communis var. saxatilis Pall., except for the Kamchatka population that was quite dissimilar to any population examined. Most likely, the current sites of all of the populations were covered with ice or otherwise inhospitable, up to or during the late Pleistocene (ca. 12,000 BP). Therefore, these populations are recent in origin. The path of re-colonization appears to have been northward in North America. Greenland appears to have been colonized from Iceland plants, which in turn came from northern Europe. The Kamchatka population seems likely to have come from Japan.