How does evolution shape the genetic polymorphisms that contribute to disease susceptibility? Polymorphism is to a large extent maintained in the human population by pathogens, and understanding the forces that maintain polymorphisms is of critical importance: for example the frequency of susceptible genotypes is a clear correlate of infection risk. Both the pattern and the specifics of host polymorphisms can instruct us how pathogens are contained and pathology minimised. In the context of chronic infections and co-infections, however, pathogen exposure may select for particularly complex and graduated genetic responses. These combinations of polymorphisms can regulate the quantitative levels of cytokines or select structural polymorphisms controlling ligand-binding by immune receptors, for example. This article was published on 2025-03-12
