Background: Amphibian populations are declining worldwide. Chytridiomycosis, an epidermal infection caused by the fungal pathogen Batrachochytrium dendrobatidis (Bd), is one of the factors implicated in these declines. In the eleven years since Bd’s identification, researchers are uncertain whether Bd is a novel or endemic pathogen, where it originated from, and how it has moved (both spatially and temporally) throughout the world. Previous research found Bd’s molecular markers too limited in number and variability to fully address Bd’s population genetics, identify where it came from geographically, or define its spatial movement. Herein I propose a rigorous population genetics study utilizing next generation sequencing technology to identify multiple, new genetic markers and apply them to a series of population genetic analyses. My research objective is to describe the evolutionary history of Bd. My overarching hypothesis is: the genetic variation among Bd isolates is correlated with its historical epidemiology.
Societal and scientific importance: There are two major scientific contributions within this research proposal. The most obvious one is finally understanding where Bd originated from and how it subsequently spread throughout the world. If conservation measures are to protect amphibians from future declines, it is important to understand where it came from and how it moves between and within amphibian communities. Most importantly, conservation programs can adjust their resources based on whether Bd is a novel or endemic pathogen. If novel, programs need to direct resources aimed at identifying and slowing disease spread. If Bd is endemic, then conservation programs need to regulate the environment and/or aspects of host biology to prevent disease outbreaks. The second major achievement this research aims to accomplish is applying cutting-edge next generation sequencing techniques to a large set of individuals, or pathogenic isolates in this case. While next generation sequencing is becoming more popular and the sought after technology, rare is it multiple, entire genomes of a non-model organism are being sequenced. Plus, the results are directly applicable to two of today’s most pressing environmental issues, as determined the National Research Council: biodiversity conservation and infectious diseases within the environment.