High Resolution Mapping of Quantitative Trait Loci Affecting Increased Life Span in Drosophila melanogaster

Limited life span and senescence are near-universal characteristics of eukaryotic organisms, controlled by many interacting quantitative trait loci (QTLs) with individually small effects, whose expression is sensitive to the environment. Analyses of mutations in model organisms have shown that genes affecting stress resistance and metabolism affect life span across diverse taxa. However, there is considerable segregating variation in life span in nature, and relatively little is known about the genetic basis of this variation. Replicated lines of Drosophila that have evolved increased longevity as a correlated response to selection for postponed senescence are valuable resources for identifying QTLs affecting naturally occurring variation in life span. Here, we used deficiency complementation mapping to identify at least 11 QTLs on chromosome 3 that affect variation in life span between five old (O) lines selected for postponed senescence and their five base (B) population control lines. Most QTLs were sex-specific, and all but one affected multiple O lines. The latter observation is consistent with alleles at intermediate frequency in the base population contributing to the response to selection for postponed senescence. The QTLs were mapped with high resolution, and contained from 12-170 positional candidate genes.

Key Words: QTLs, aging, deficiency mapping, postponed senescence

Online ISS 1091-6490
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