Enviromics: understanding aging

Human aging is determined by interactions between genetic and environmental factors. Although variations in the rate of aging across species suggests a strong role of genetics, heritability of lifespan observed within each species is < 35% [1], indicates that the environment plays an predominant role in aging. The reliability theory of aging portrays organisms as mechanical systems that contain components with varying probabilities of failure [2]. Complex organisms have redundancy in vital systems (perhaps better understood as the capacity to self-repair) so that every occurrence of damage does not result in death, but rather, the organism accumulates defects (due to inefficient repair) that ultimately exhaust reparative capacity. While in the context of this theory, the frequency and severity of damage has been thought to be determined, at least in part, by the environment, there are few, if any, conceptual models with robust explanatory power and predictive capacity to account for the influence of the environment on the rate of aging. In this regard, the concept of the envirome, analogous to the genome, could provide a useful ontological model for studying the relationship between the environmental circumstance and genetic predisposition [3,4]