Our primary goal is to determine the molecular and evolutionary processes that shape host-microbe associations, particularly between animals and pathogenic bacteria. Below are some examples of current project areas in the lab.


Infectious diseases are a potent force of natural selection. Repeated episodes of adaptation at host-microbe protein interfaces can lead to molecular ‘arms races,’ providing some of the most dramatic examples of rapid evolution observed in nature.

Recently we have been studying interactions between bacteria and primates relating to the essential micronutrient iron. In addition to dedicated immune defenses, the sequestration of iron by host proteins provides a potent barrier to infection termed nutritional immunity. Microbes in turn deploy dedicated iron acquisition factors, including secreted siderophores and cell surface receptors, in order to scavenge this nutrient from the host. Our research indicates that this ‘battle for iron’ has been a hotspot of evolutionary conflict during millions of years of primate divergence, driving rapid diversification of proteins that contributing to nutritional immunity. We are continuing to investigate evolutionary conflicts between bacteria and primate hosts in relation to additional antibacterial immune defenses.


Long-term coevolution of microbes and hosts has produced an array of remarkable biological innovations including adaptive immunity in vertebrates as well as CRISPR-Cas defense systems in bacteria and archaea. How has the amazing complexity of the immune system evolved, and what unique activities remain to be discovered? We are currently exploring the processes by which new protein functions emerge as a consequence of host-microbe associations as well as strategies to engineer the activity of existing proteins.


Many bacteria are restricted to life in a single host species, but the mechanisms underlying this specificity are often mysterious. In addition, numerous bacteria capable of causing disease in humans colonize a large proportion of the populations asymptomatically. One of our emerging goals is to determine the genetic and molecular basis by which bacteria adapt to the host environment and identify factors that impact host-associated bacterial behavior. In addition to advancing our understanding of the fundamental process of adaptation, pinpointing the determinants of host specificity in human pathogens could reveal new avenues for infectious disease treatment and prevention.


Current research sponsors:



Past research sponsors:


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