Re-examining heritability: genetics, life history and plasticity

Human life-history traits (growth, maturation, nutritional status) are increasingly associated with risk of chronic degenerative disease. Twin studies suggest high heritability of such traits; however, although sophisticated approaches have identified genetic variation underlying a proportion of this heritability, studies also increasingly demonstrate significant plasticity, and many life-history traits are able to change by one standard deviation (SD) over 3–6 generations. Developments in our understanding of the contributions of genetics and plasticity to human life history are likely to improve understanding of the growing burden of chronic diseases. We argue that a life-history approach to understanding variation in the human phenotype must integrate these two risk components, and highlight the important contribution of plasticity to changes in disease prevalence.