About This Project

Frogs are experiencing global declines because of emerging pathogens. Understanding how populations cope with these pathogens is essential for their conservation. We plan to investigate how genetics influences differential outcomes in populations. Some genes have been looked at, but we need a better view across the whole genome. We plan to use DNA extracted from frogs from museums and compare it to modern population DNA to see how population genetics have changed after disease introduction.

Ask the Scientists

What is the context of this research?

Amphibians are facing a biodiversity crisis in part due to two pathogens: the Ranavirus Frog Virus 3 (FV3) and the chytrid fungus Batrachochytrium dendrobatidis (Bd). These pathogens can cause severe symptoms and sometimes death in amphibians, including frogs and my focal species the green frog. We can use population genetics to understand what allows, or hinders, populations to persist when facing these pathogens. Disease susceptibility and mortality have a genetic component as shown by different outcomes to FV3 and Bd infection across species, populations, and individuals. Two genes have been implicated: MHC I and MHC II. Research shows that infected individuals are more likely to have particular genetic variants, and that pathogen introduction leads to a decrease in genetic diversity over time. Museum collections are a great way to study changes in population genetics before and after pathogen introduction.

What is the significance of this project?

For effective wildlife management, we must understand how frog populations adapt to FV3 and Bd. This research will identify vulnerable populations to disease based on population genetics and diversity. It is important to maintain genetic diversity because it makes populations more resilient to new stressors. Genetic diversity can also be used to estimate changes in population size and if populations have declined. Additionally, by looking at the genetic sequences of individual frogs with different disease tolerances, we can identify genetic markers that can be used to evaluate other populations. Using these markers, population risk can be assessed before pathogen introduction and prioritize vulnerable populations for conservation. Natural history collections offer an underutilized wealth of biodiversity data that will be capitalized on in this study. My study will contribute to the growing work of knowledge that highlights museums’ role in modern biodiversity and conservation research.

What are the goals of the project?

My study uses a collection of modern samples and museum specimens to compare how population genetics change before and after FV3 and Bd introduction to Vermont. Modern samples include individuals that are both infected and non-infected with the two pathogens and come from pond communities with and without the pathogens present. First, I will extract DNA from museum specimens. I will sequence the DNA to get two different pieces of info. First is sequencing important parts of the two immune genes MHC I and MHC II. Second is sequencing representatively across the genome to pick up DNA sequences that are not under selection. The sequence data will let me calculate genetic diversity in the historic and modern populations and estimate changes in population size. I will also identify genetic variants that are associated with disease susceptibility and tolerance. The funds raised will be used to help prepare DNA samples and complete sequencing.