The evolution of aging and lifespan

Abstract

Aging is a nearly inescapable trait among organisms yet lifespan varies tremendously across different species and spans several orders of magnitude in vertebrates alone. This vast phenotypic diversity is driven by distinct evolutionary trajectories and tradeoffs that are reflected in patterns of diversification and constraint in organismal genomes. Age-specific impacts of selection also shape allele frequencies in populations, thus impacting disease susceptibility and environment-specific mortality risk. Further, the mutational processes that spawn this genetic diversity in both germline and somatic cells are strongly influenced by age and life history. We discuss recent advances in our understanding of the evolution of aging and lifespan at organismal, population, and cellular scales, and highlight outstanding questions that remain unanswered.

Keywords: aging; diversity; evolution; genetics; lifespan; mutation.

Figure 1:

Evolutionary dynamics underlying aging and longevity. The interplay between genes, life history traits, and environmental factors drives the evolution of aging and lifespan. Highlighted above are several of the key elements in each domain that have known associations with aging and longevity. The iconography in the center of the figure depicts differences in lifespan (candle height) and their evolutionary relationships, in the Vanitas style.

Figure Box 1:

Mortality hazard (instantaneous probability of death) and survival curves for six diverse species. Mortality hazard lines become dotted after the maximum lifespan of the species.