Most alpine-artic plants were hypothesized to have originated from the Qinghai-Tibetan Plateau and adjacent alpine regions. However, this hypothesis was rarely examined and tested for those plants occurring in these regions by the current population genetic data and the following modeling tests. In this project, we select Oxyria digyna, a widely distributed species in the alpine and artic regions of the Northern Hemisphere as a model to conduct such studies. Based on the available samples across its distribution over the Northern Hemisphere, we will collect population genetic data and genetic variations from chloroplast DNA and multiple nuclear loci. Then we will use multiple approaches, including coalescent analyses and modeling tests, to reconstruct lineage differentiation and population dynamics of each local populations, and finally to identify the origin of this species, glacial refugia and recolonization routes. Our results will provide a case study for out-of-Qinghai-Tibetan Plateau hypotheses for some temperate plants.