Pleistocene Glacial Effects on North American Phylogeographic Patterns

Project Abstract

The biodiversity of alpine ecosystems are grossly underestimated, in turn threatening habitat loss. Much work is needed in this respect to better understand the process of speciation and extinction in these environments, given the threat of global climate change. We are testing hypothesis regarding rapid radiation of plant lineages both into and out of glacial refugia in the context of dispersal during post-glacial and inter-glacial periods, focusing on the phylogeny of trans-Beringian alpine plant species by observing lineages extending into southern portions of the North American Cordillera, the Rocky Mountains and the Intermountain Region. Focal taxa include species of Draba (Brassicaceae), Claytonia (Montiaceae), Potentilla (Rosaceae), Campanula (Campanulaceae), Oxytropis (Fabaceae), Acontium (Ranunculaceae) and Silene (Caryophyllaceae). We hypothesize that alpine lineages occupying regions repeatedly glaciated during the Pleistocene epoch will differ from consistently unglaciated lineages due to vicariance events reducing gene flow, effecting intrapopulation and interpopulation genetic diversity. We predict that these glaciated alpine lineages will exhibit lower intrapopulation genetic diversity and higher interpopulation genetic diversity than populations from continuously glaciated regions due to increased vicariance events, thus reduced gene flow and smaller population sizes. Integrating population genetics, phylogeny, polyploid analyses, and phylogeography allows for direct correlation between the historical environmental impacts of glaciation events and the levels of extant genetic diversity. For this, we identified multiple localities in the western United States for focal taxa occupation, glaciated and unglaciated areas, and accessibility. In summer 2022 and 2025, we visited these localities and collected population-level samples for DNA extraction and Genotyping by Sequencing with ddRADtag library preparation during the winter months.

Conference

87th Annual Meeting of the Association of Southeastern Biologists, March 20-26 2026, Association of Southeastern Biologists. https://www.sebiologists.org/asb-2026.html

Funding Type

Travel Grant

Academic College

Jesse D. Jones College of Science, Engineering and Technology

Area/Major/Minor

Biology

Degree

Bachelors

Classification

Sophomore

Name

Ingrid Jordon-Thaden, PhD

Academic College

Jesse D. Jones College of Science, Engineering and Technology

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