NSF Postdoctoral Fellowship in Biology FY 2018 - Testing the Oscillation Hypothesis of Symbiont Diversification using Parasites Isolated from Host Tissue Collections

Galen Spencer, Hoboken NJ

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. The title of the research and training plan for this fellowship to Spencer Galen is "Testing the Oscillation Hypothesis of Symbiont Diversification using Parasites Isolated from Host Tissue Collections" The host institution for the fellowship are the Academy of Natural Sciences of Drexel University (ANSDU) and the sponsoring scientist is Dr. Jason Weckstein. The goal of this research is to identify the factors that influence the diversification and distribution of symbiotic organisms (organisms that live in close association with a host), a group that is thought to comprise the majority of species on Earth. Symbionts play critically important roles in the function of ecological communities worldwide, though the traits and general rules that have produced modern symbiont diversity are still poorly understood. This project will gain insight into the patterns and processes that have resulted in the incredible diversity of modern symbionts by studying an expansive collection of avian malaria parasites, a symbiont group that is closely related to the deadly human malaria parasites. Specifically, this research will examine how variation in the number of host species that a parasite can infect, known as "host breadth", influences a parasite's potential to diversify or colonize new geographic regions. By analyzing the host breadth of malaria parasites that have been isolated from a large collection of avian tissues sampled across North and South America, this research will improve our understanding of how parasites and symbionts more broadly have come to be so exceptionally diverse and have attained their current distributions. In addition, studying the causes of parasite diversification and distributions will lead to a better understanding of when and where novel disease-causing parasite species originate, a problem of major importance in today's rapidly changing world. Training objectives include sequence capture probe design and implementation, phylogenomic analysis, phylogenetic comparative analysis, and methods used in parasite specimen acquisition, accession, and curation. Broader impacts include outreach importance of symbionts to educational camps at the ANSDU and the mentoring of high school and undergraduate students through the Students Tackling Advanced Research (STAR) Scholars in Natural Sciences programs. The Fellow will use the oscillation hypothesis of symbiont diversification as a framework to test the effect of host breadth on parasite geographic range evolution and diversification. This research will utilize malaria parasites isolated from a geographically and taxonomically expansive collection of avian tissues located at the ANSDU and the Field Museum of Natural History. Malaria parasite genetic data will be collected using a novel exon capture probe design to estimate a robust phylogeny for the group and thousands of avian tissue samples will be tested for malaria infection to estimate parasite host breadth and geographic range size metrics. Data from this project will be analyzed using phylogenetic comparative methods to test for associations between host breadth evolution, geographic range shifts, and malaria diversification. To promote the use of and increase accessibility of project outcomes, all products from this research will be made available on public repositories (GenBank, Dryad, ParaSite, MalAvi). In addition, specimens involved in this research will be vouchered in public research institutions, and the research will be published in open-access journals. Keywords: Diversification, Host breadth, Malaria parasites, Oscillation Hypothesis, Phylogenomics, Sequence Capture 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.