Article
Genotyping-by-sequencing and ecological niche modeling illuminate phylogeography, admixture, and Pleistocene range dynamics in quaking aspen (Populus tremuloides)
PeerJ Preprints
(2018)
Abstract
Populus tremuloides is the widest-ranging tree species in North America, and an ecologically important component of mesic forest ecosystems displaced by the Pleistocene glaciations. Using phylogeographic analyses of genome-wide SNPs (34,796 SNPs, 183 individuals) and ecological niche modeling, we inferred population structure, admixture, and Pleistocene range dynamics of P. tremuloides, and tested several historical biogeographical hypotheses. We found three genetic lineages located in coastal (cluster 1), Cascadian/Northern Rocky Mountains (cluster 2), and Southern Rocky Mountains to northern regions (cluster 3) of the P. tremuloidesrange, with phylogenomic relationships of the form ((cluster 1, cluster 2), cluster 3). The main vector of admixture was from cluster 3 into cluster 2, with the admixture zone trending northwest through the Rocky Mountains along a recognized phenotypic cline (Utah to Idaho). Clusters 1 and 2 provided mixed support for the ‘stable-edge hypothesis’ that unglaciated southwestern populations persisted in situ since the last glaciation. By contrast, cluster 3 exhibited ‘trailing-edge’ dynamics, e.g. clinal genetic variation and niche suitability predictions signifying complete northward post-glacial expansion. Results were also consistent with the ‘inland dispersal hypothesis’ predicting post-glacial assembly of Pacific Northwestern forest ecosystems, but rejected the hypothesis that Pacific-coastal populations were colonized during outburst flooding from glacial Lake Missoula. Overall, congruent patterns between our phylogeographic and ecological niche modeling results and fossil pollen data demonstrate complex mixtures of stable- versus trailing-edge dynamics and refugial locations within P. tremuloides. These findings confirm and refine previous genetic studies, while strongly supporting a distinct Pacific-coastal genetic lineage of quaking aspen.
Disciplines
Publication Date
2018
DOI
https://doi.org/10.7287/peerj.preprints.27162v1
Citation Information
Karen E. Mock. "Genotyping-by-sequencing and ecological niche modeling illuminate phylogeography, admixture, and Pleistocene range dynamics in quaking aspen (Populus tremuloides)" PeerJ Preprints Vol. 6 (2018) p. e27162v1 Available at: http://works.bepress.com/karen_mock/163/