Abstrakt
To quantify the force of selection, Hamilton [Hamilton, W. D. (1966) J. Theor. Biol. 12, 12-45] derived expressions for the change in fitness with respect to age-specific mutations. Hamilton's indicators are decreasing functions of age. He concluded that senescence is inevitable: survival and fertility decline with age. I show that alternative parameterizations of mutational effects lead to indicators that can increase with age. I then consider the case of deleterious mutations with age-specific effects. In this case, it is the balance between mutation and selection pressure that determines the equilibrium number of mutations in a population. In this balance, the effects of different parameterizations cancel out, but only to a linear approximation. I show that mutation accumulation has little impact at ages when this linear approximation holds. When mutation accumulation matters, nonlinear effects become important, and the parameterizations of mutational effects make a difference. The results also suggest that mutation accumulation may be relatively unimportant over most of the reproductive lifespan of any species.
Originalsprog | Engelsk |
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Tidsskrift | Proceedings of the National Academy of Science of the United States of America |
Vol/bind | 102 |
Udgave nummer | 23 |
Sider (fra-til) | 8263-8 |
Antal sider | 6 |
ISSN | 0027-8424 |
DOI | |
Status | Udgivet - 7. jun. 2005 |
Udgivet eksternt | Ja |
Emneord
- Aging
- Biological Evolution
- Fertility
- Longevity
- Models, Genetic
- Mutation
- Reproduction
- Selection, Genetic
- Survival Rate