Protection from epidemics is a driving force for evolution of lifespan setpoints

Abstract

Most living organisms age, as determined by species-specific limits to lifespan1-6. The biological driving force for a genetically-defined limit on the lifespan of a given species (herein called \"lifespan setpoint\") remains poorly understood. Here we present mathematical models suggesting that an upper limit of individual lifespans protects their cohort population from infection-associated penalties. A shorter lifespan setpoint helps control pathogen spread within a population, prevents the establishment and progression of infections, and accelerates pathogen clearance from the population when compared to populations with long-lived individuals. Strikingly, shorter-living variants efficiently displace longer-living individuals in populations that are exposed to pathogens and exist in spatially structured niches. The beneficial effects of shorter lifespan setpoints are even more evident in the context of zoonotic transmissions, where pathogens undergo adaptation to a new host. We submit that the selective pressure of infectious disease provides an evolutionary driving force to limit individual lifespan setpoints after reproductive maturity to secure its kins fitness. Our findings have important public health implications for efforts to extend humans lifespan.