Long-lived genotypes for studies of life extension in Drosophila melanogaster

Numerous single-gene mutations obtained by insertion of P elements in white (w) genetic backgrounds have been reported to extend the life span of Drosophila melanogaster, but life extension is sometimes observed only in relatively short-lived backgrounds. The objective of this study was to develop long- and short-lived, high and low fertility backgrounds in which to test the reproducibility and possible additivity of effects of prospective life-extending treatments. Flies previously reported to be long- or short-lived, following artificial selection for early or delayed reproduction and inbreeding, were rendered essentially isogenic, and a w visible marker was introduced. Isogeny adversely affected both life span and fertility, but w had little or no effect on either trait. Unexpectedly, none of these lines or a stock under uninterrupted selection for delayed reproduction lived any longer than an unselected, highly fertile y w strain used in earlier studies of longevity. Strains derived from one artificial selection experiment were found to contain functional P elements, as did the two longest-lived genotypes in this study, which were inbred without artificial selection. The y w background appears to be at least equally as long-lived as any other currently available for tests of life extension by P{w(+)} mutations.