This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5).
Mammals, including humans, have extremely high genetic diversity among the genes involved in the immune system. The resulting differences among individuals are thought to help reduce the severity of infectious diseases affecting a population. But the mechanisms whereby this occurs are not fully known. One leading explanation is that hosts and pathogens are constantly evolving to outmaneuver each other in a so-called molecular arms race. A host population that lacks sufficient genetic variation would tend to lose this race because it would be more susceptible to the evolution of virulent pathogens. This study tests predictions of this hypothesis by allowing two viruses to adapt to specific host strains over many generations, and testing whether the resulting pathogens are more virulent and why.
The broader impacts of this research include improved understanding of pathogen-caused health problems for humans, agricultural species and wildlife, the evolution of emerging diseases including bioterrorism agents, and reducing the impact of pathogens on endangered species. Climate change and other human activities will cause an estimated ¼ of earth's vertebrate species to become endangered during the next 20 years. These endangered species suffer reduced genetic diversity and the dismal 11% success rate for their reintroduction may be due in part to rapid evolution of pathogens.
This project for the first time directly tests this hypothesis in vertebrates and provides the groundwork for identifying critical host genetic diversity needed to slow the evolution of virulent pathogens. This project also provides training and employment for numerous students in an interdisciplinary context.
