The genetic basis of aging: an evolutionary biologist's perspective.

This Perspective discusses recent progress in the study of the genetic basis of aging from the viewpoint of an evolutionary biologist. Work in this area has revealed that homologous genes and pathways play a role in determining life span in many different species. Because life span is a complex polygenic trait, however, these findings provide information about only a small portion of the genetic basis of this trait. Additionally, because the model organisms used to study aging have been exposed to similar laboratory conditions that can lead to unintentional artificial selection, some of the similarities among these organisms might have resulted from such selection. It is not yet clear whether the results found in model organisms will extend to organisms in a natural environment. A few species are known for which there are natural populations that differ in life span and patterns of senescence, and they should be useful for assessing whether the genetic mechanisms identified in the laboratory also operate in the wild.