My work is at the interface of mathematics and the epidemiology and evolution of pathogens. I hold an Canada 150 Research Chair in Mathematics for Evolution, Infection and Public Health. In my group we develop mathematical tools connecting sequence data to the ecology and evolution of infections. I also have a long-standing interest on the dynamics of diverse interacting pathogens. For example, how does the interplay between co-infection, competition and selection drive the development of antimicrobial resistance? To answer these questions, my group is building new approaches to analyzing and comparing phylogenetic trees derived from sequence data, studying tree space and branching processes, and developing ecological and epidemiological models with diversity in mind.