DIRECT SELECTION ON LIFE SPAN IN DROSOPHILA MELANOGASTER

Area of Science:

• Evolutionary biology
• Gerontology
• Genetics

Background:

• The evolution of aging is often studied by selecting for reproductive timing in Drosophila melanogaster.
• A key question is whether reduced early fecundity is linked to increased lifespan.
• Previous studies using selection on age at reproduction yielded conflicting results.

Purpose of the Study:

• To investigate the relationship between longevity and fecundity in Drosophila melanogaster.
• To determine if direct selection for lifespan affects early and late reproductive output.
• To test the disposable soma theory of aging.

Main Methods:

• Experimental evolution using direct selection for short and long lifespan in Drosophila melanogaster.
• Monitoring of fecundity, starvation resistance, and fat content in selected fly populations.
• Comparison of results with previous studies using selection on age at reproduction.

Main Results:

• Direct selection successfully altered lifespan in both short and long-lived lines of fruit flies.
• Longer-lived females exhibited consistently lower progeny production throughout their lives.
• No increase in late-life reproduction was observed in long-lived females, unlike in previous studies.
• Short-lived flies showed reduced starvation resistance and fat content.
• Data support the negative-pleiotropy-disposable-soma theory of aging.

Conclusions:

• Lifespan in Drosophila melanogaster can be genetically modified through direct selection for longevity.
• Increased lifespan is associated with decreased overall and early reproduction.
• The findings suggest a trade-off in resource allocation, potentially involving lipid metabolism, between maintenance and reproduction.
• Further research, including male reproduction, is needed to fully understand these mechanisms.