A test of evolutionary theories of aging.
Senescence is a nearly universal feature of multicellular organisms, and understanding why it occurs is a long-standing problem in biology. The two leading theories posit that aging is due to (i) pleiotropic genes with beneficial early-life effects but deleterious late-life effects ("antagonistic pleiotropy") or (ii) mutations with purely deleterious late-life effects ("mutation accumulation"). Previous attempts to distinguish these theories have been inconclusive because of a lack of unambiguous, contrasting predictions. We conducted experiments with Drosophila based on recent population-genetic models that yield contrasting predictions. Genetic variation and inbreeding effects increased dramatically with age, as predicted by the mutation theory. This increase occurs because genes with deleterious effects with a late age of onset are unopposed by natural selection. Our findings provide the strongest support yet for the mutation theory.
Hughes
Kimberly A
KA
School of Integrative Biology and Program in Ecology and Evolutionary Biology, University of Illinois, Urbana, IL 61801, USA. kahughes@uiuc.edu
Alipaz
Julie A
JA
Drnevich
Jenny M
JM
Reynolds
Rose M
RM
D000375:Aging / Q000235:genetics* / Q000502:physiology; D000818:Animals; D004331:Drosophila melanogaster / Q000235:genetics* / Q000502:physiology; D019143:Evolution, Molecular; D005260:Female; D007178:Inbreeding; D008297:Male; D012098:Reproduction / Q000502:physiology