Selection for Increased Longevity in <i>Drosophila melanogaster</i>: Reflections on New Data

Abstract

In recent papers, new data were presented on the late-age reproduction experiment initiated by Luckinbill and Clare in 1981: when early- and late-reproduced lines were compared simultaneously 10 years after the end of the original experiment, differences in the mean life span are observed between the lines. Yet the conditions in which these measurements were done are highly questionable. More fundamentally, using these data, the analysis of the selection process is impossible and conclusions about the determinism of life span are debatable.

Dissecting the genetics of longevity inDrosophila melanogaster

“…95 Artificial selection on multiple traits has demonstrated phenotypic responses in longevity, including selection on time of reproduction, 84,85,96-100 stress tolerance, 86,87 and response to diet quality. 101 While inconsistencies have been observed, [102][103][104][105] these studies clearly demonstrate that wild-derived lines harbor genetic variation at loci that affect aging, and that longevity tends to correlate negatively with reproduction and positively with stress and starvation tolerance. One study has performed direct artificial selection on lifespan in D. melanogaster, 106 and results support these same correlations between longevity, reproduction and stress tolerance.…”

A mini-review of the evolutionary theories of aging.

“…If longevity differs along months, as in Lints et al (1989), it could bias the results. As a matter of fact, Baret and Lints (1993) showed that, when the Clare and Luckinbill's results (1985) are expressed as a function of calendar time, and not of generation number, the difference between YOUNG and OLD lines is erased. In other words, when YOUNG and OLD flies living at the same moment are compared, there is no longevity difference between them.…”

“…However, Baret and Lints (1993) reanalysed the Clare and Luckinbill's results (1985). They noticed that, since YOUNG and OLD lines are reproduced at different ages, the same generation number occurs at a different calendar time in the two lines.…”

“…In other words, when YOUNG and OLD flies living at the same moment are compared, there is no longevity difference between them. This article provoked considerable attention (see the debate in Gerontology: Fukui, Pletcher and Curtsinger 1995;Arking and Buck 1995;Baret, Le Bourg and Lints 1996). Arking and Buck (1995) published new results using the lines of Luckinbill et al (1984) showing clear differences between OLD and control lines reproduced at random age.…”

Realized Heritability of Longevity in <i>Drosophila melanogaster</i>

“…These experiments gave contradictory results. More over the interpretation o f the data was made difficult because o f the impossibility o f mea suring a given generation at the same time, both in the control line (reproduced at early age) and in the selected line (reproduced at late age) [3].…”