Evolution of Human Longevity and the Genetic Complexity Governing Aging Rate
The genetic complexity of processes governing the aging rate of humans was estimated by determining the maximum rate at which life-span has evolved along the hominid ancestral-descendant sequence. Maximum life-span potential was found to have increased approximately twofold over the past 3 million years, reaching a maximum rate of increase of 14 years per 100,000 years about 100,000 years ago. It is estimated that about 0.6% of the total functional genes have received substitutions leading to one or more adaptive amino acid changes during this 100,000-year time-period. This suggests that aging is not the result of the expression of a large number of independently acting processes. Instead, primary aging processes appear to exist in which only a few genetic changes are necessary to uniformly decrease the aging rate of many different physiological functions. Reproduced by permission. Richard G. Cutler, Evolution of Human Longevity and the Genetic Complexity Governing Aging Rate. Proc. Natl. Acad. Sci. U.S.A. 72 , 4664-4668 (1975).