Relationship between life expectancy and endogenous DNA single-strand breakage, strand break induction and DNA repair capacity in the adult housefly, Musca domestica

Abstract

The objective of this study was to investigate the relationship between genomic damage and the physiological rate of aging. Endogenous DNA single-strand breaks, susceptibility of DNA to exogenously induced strand breaks and the capacity to repair strand breakage were compared, using the alkaline elution technique, in flies of the same chronological age but with different life expectancy. Distinctions between physiological and chronological ages were made (1) by experimentally altering the life spans of houseflies by varying the level of physical activity, and (2) by phenotypic selection of short- and long-lived cohorts from the same population. The degree of endogenous DNA single-strand breaks was found to be unrelated to physiological age. However, flies selected for relatively shorter life expectancy exhibited a greater susceptibility to exogenously-induced (gamma-irradiation) single-strand breakage. Flies with a longer life expectancy exhibited a more efficient repair capacity to reverse single-strand breakage than those with a shorter life expectancy.