Brian Lazzaro

Our research is focused on the evolutionary genomics of insect-pathogen interactions, emphasizing such questions as how natural selection operates on host immune systems and why individuals vary in susceptibility or resistance to infection. In my group, we like to think of the host as an assemblage of interacting physiological processes, where the immune system is embedded in the overall physiological context of the host. This motivates us to consider effects of abiotic environment on immune defense and means that genetic determination of variation in resistance may lie in genes outside of the canonical immune system. This thinking also extends directly to the evolution and mechanism of life history constraints. Importantly, the host is itself the "environment" in which an infecting pathogen lives, and differences in host physiological state or abiotic environment can alter microbial behavior and therefore ultimate outcomes of infection. Our overarching goal is to consider host and pathogen as interacting components of a single system, shaped by the environment. We primarily use bacterial infection in Drosophila melanogaster as an experimental model to deconstruct elements of the unified system, studying components in tractable modular pieces. Understanding the dynamics of unified host-pathogen-environment systems is crucial because these dynamics determine the ecology and evolution of disease in natural settings with consequence at higher biological scales.