Which role do genes play during the host defense against an infection? What is the contribution of environmental factors? Can we study this complex interaction of genes and environment in silico? We can now start to ask these questions because, in recent years, we have gained an enormous knowledge about the genes and their functions in the mouse and human organism. The researchers in the Department of Infection Genetics are seeking to answer such questions. They study how genes and their different variants can positively or negatively influence the host response to an infection with influenza A virus.