History of the Arctic Flora in North America

This dataset in an attempt to increase understanding of how climate cycles of the Quaternary (the last 2.6 million years) impacted divergence in Arctic and alpine tundra flora. Specimens were collected in Beringia and the mountains of western North America, focusing on populations existing within (western and eastern Beringia, and the Pacific Northwest and Rocky Mountains, respectively), as well as sites between those refugia. Briefly, DNA was sequenced from chloroplast and nuclear loci for multiple species of tundra plants that inhabited the entire study region. Target species (Campanula species, Kobresia myosuroides, Lloydia serotina, Pinguicula vulgaris, Poa alpina, Rhodiola species, and Saxifraga species) were phylogenetically diverse and displayed a range of dispersal abilities, making them excellent candidates for evaluating general history of the tundra. Those genetic data make up this Arctic Flora dataset. From the genetic sequence data, gene trees are being reconstructed and used to estimate the patterns and timing of divergence, test which geologic and climatic events most impacted divergence, and infer how the process of genetic divergence differed between Arctic and alpine tundra refugia.

The data is archived in nexus files - the standard format for aligned sequence data ready to be used in a phylogenetic analysis. The files are separated by taxon and genetic locus within a given taxon. The nexus format provides details on the data type (DNA), number of samples, and length of sequence. Within a file, all the sequences are aligned but not interleaved, such that the 'sample name' is followed by the entire sequence for that sample. All the specimens that were collected are archived and publicly accessible in the Western Washington University Herbarium.