The Persistence of Naturally Selected Resistance to Infectious Crowd Disease

Justin Cook, Yale University

This paper investigates the role of genetic differences in resistance to infectious diseases on contemporary health outcomes. The Neolithic Revolution constituted a major environmental shift that led to the initiaition and sustainability of new infectious diseases. The differential timing of the Neolithic Revolution created differences in exposure to infectious pathogens. Ultimately, this led to differential selection of genetic resistance, in which diversity within a component of the immune system, the major histocompatibility complex, was favorable. We evaluate this advantage through the construction of a common measure of genetic diversity that is constructed solely from gene variants within the major histocompatibility complex, known as the human leukocyte antigen (HLA) system in humans. Our estimations imply greater HLA genetic variation is associated with better pre-medicinal health outcomes. Specifically, our baseline estimates show a ten percent increase in HLA genetic diversity is associated with a five percent increase in life expectancy in 1960.