NSF Postdoctoral Fellowship in Biology FY 2018

Wefferling Keir M, Milwaukee WI

Investigators

Abstract

This action funds an NSF Postdoctoral Research Fellowship in Biology for FY 2018, Research Using Biological Collections. The fellowship supports research and training of the fellow that will utilize biological collections in innovative ways. This study of goldback ferns (Pentagramma; Pteridaceae) investigates the evolutionary and ecological implications of polyploidy (whole genome duplication) and hybridization (genome merging) in nature. Hybridization and polyploidy exert long-term effects on the evolution of lineages across the tree of life. However, only recently have we had the tools to address the impacts of these processes on evolution. This research addresses long-standing questions about evolution, such as the relative contribution of genome duplication versus genome merging in the ecological and evolutionary success of polyploids, and how genome and cell size vary across the landscape. This work will enhance the usefulness of museum specimens through novel, cost-effective, and high-throughput approaches that can be applied to other systems. Conceptualizing polyploid formation as taking place at various positions along a polyploid spectrum?measured by polyploid subgenome divergence?provides a framework in which to test the ecological and genetic determinants of polyploid success. In order to delineate diploid and polyploid species and address geographic, ecological, and phenotypic effects of subgenome divergence in Pentagramma, the fellow will: 1) assess ploidy levels and genome size specimens using a combination of chromosome counts and flow cytometry; 2) infer phylogenetic relationships among diploids and polyploids using chloroplast and nuclear markers; 3) measure genetic distance between polyploid subgenomes; 4) compare geographic range and niche breadth between and among diploids and polyploids; 5) measure spore size, exudate quantity, and chemotype; and 6) assess correlations between subgenome divergence and spatial variables, and among phenotypic traits and spatial variables. These data will allow for a test of the hypothesis that polyploids are most successful when formed between progenitors with intermediate levels of divergence. The use of museum specimens as a source of material for ecologically relevant data is highly important for studies of fern evolution and ecology. This approach will retrieve genomic data from old and degraded samples and can serve as a proof of concept for other studies relying on biological collections of similar samples. In order to promote the sharing of tools and research results, the fellow will lead workshops and seminars at the University of California, Berkeley Botanical Garden, California Academy of Sciences, and regional universities. Public outreach will target local elementary, middle, and high school students. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.