Brief Study Abstract: We inferred the phylogeographic history of Populus tremuloides by combining broad scale inferences of population structure, admixture, and ploidy based on genome-wide SNP data with spatially explicit predictions of the past to present geographical distributions of the species and its intraspecific lineages (genetic "clusters") using ecological niche modeling (ENM) hindcasting. Under this framework, we found strong evidence for significant patterns of population divergence and admixture among three intraspecific genetic clusters, including a new and genetically distinct lineage of Pacific-coastal aspen. Our results from integrating these approaches to analyze intraspecific genetic clusters within P. tremuloides also obtained strong support for stable-edge dynamics, but mixed support for trailing-edge dynamics. Overall, our findings agree well with the previous genetic results but present a more nuanced picture of P. tremuloides evolution and diversification refining the geographical positions of genetic subdivisions, past or ongoing admixture, and putative Pleistocene refugia.
Brief Data Overview: Accessioned in this project are the raw data from P. tremuloides populations sampled and sequenced for our study (Bagley et al. in press). As described in the corresponding manuscript, these raw data were processed (e.g. quality control) and combined with existing datasets from Schilling et al. (2014; provided by K. E. Mock). We then conducted genomic assembly and single nucleotide polymorphism (SNP) calling on the combined dataset, and used the resulting SNPs in our downstream genetic analyses. See additional information in Bagley et al. (in press) and the Mendeley Data accession for that paper (https://doi.org/10.17632/ jhkhv dgyfy.2).
REFERENCES
Bagley, J. C., Heming, N. M., Gutierrez, E. E., Devisetty, U. K., Mock, K. E., Eckert, A. J., and Strauss, S. H. (in press) Genotyping-by-sequencing and ecological niche modeling illuminate phylogeography, admixture, and Pleistocene range dynamics in quaking aspen (Populus tremuloides). Ecology and Evolution.
Schilling, M. P., Wolf, P. G., Duffy, A. M., Rai, H. S., Rowe, C. A., Richardson,
B. A., and Mock, K. E. (2014). Genotyping-by-sequencing for Populus population genomics: An assessment of genome sampling patterns and filtering approaches. PLoS ONE, 9(4), e95292. Less...