Landscape and Conservation Genomics of North American Ash Species

Abstract:
Climate change and invasive pests pose threats to native species and ecosystems worldwide. Western North America is a highly species and ecologically diverse region that has been experiencing the effects of decades long mega-drought and recent destructive species invasions. Two focal taxa of my research have been Artemisia tridentata, big sagebrush, and Fraxinus latifolia, Oregon Ash. Artemisia tridentata is a keystone species of the intermountain west in North America. Though this species is widespread, it is in decline due to human activity and altered fire regimes. Fraxinus latifolia, Oregon ash, is a characteristic species of riparian habitats of western North America. While climate change and human activity greatly threatens this species, its greatest threat is the invasive emerald ash borer (EAB) beetle. For A. tridentata, a drought Genotype × Environment experiment including plants from geographically distinct populations with differing precipitation regimes was conducted to induce drought stress for transcriptomic analyses. Genome re-sequencing of plants from these populations revealed differential enrichment of transposable elements clades between populations that may drive differences in expression patterns. This work demonstrates that populations of Artemisia tridentata are likely locally adapted to their respective precipitation regimes, having great implications for conservation and reseeding efforts in light of rapid environmental changes. For Fraxinus latifolia, a reduced representation sequencing method was used to generate data for (42,759 SNPs) for 61 populations across the species’ range to inform gene conservation and establishment of genecological resources needed for proactive conservation and breeding. Landscape genomic analyses revealed strong genetic structure along a north to south latitudinal gradient. Despite evidence of potential migration corridors, estimates of genetic variation and effective population size estimates appear low across all populations, suggesting that the patchy distribution of F. latifolia across its range may impact longer-term evolutionary potential of the species.

About the Speaker:
Anthony received his BS in Biology from the University of Montevallo in Alabama. He received his PhD at the University of Florida where his dissertation focused on testing genetic and ecological hypotheses for the origins of the eastern Asia - eastern North American floristic disjunction and species richness anomaly. After completing his PhD, he was a postdoctoral research associate at Boise State University, where he studied the genomic underpinnings of drought stress response in big sagebrush, Artemisia tridentata. In the Hamilton lab at Penn State University, Anthony is contributing to landscape and conservation genomics research in Ash species (Fraxinus).

Contact

Jill Hamilton
jvh6349@psu.edu