What do we mean by aging? Questions and perspectives revealed by studies in Drosophila

What is the nature of aging, and how best can we study it? Here, using a series of questions that highlight differing perspectives about the nature of aging, we ask how data from Drosophila melanogaster at the organismal, tissue, cellular, and molecular levels shed light on the complex interactions among the phenotypes associated with aging. Should aging be viewed as an individual's increasing probability of mortality over time or as a progression of physiological states? Are all age-correlated changes in physiology detrimental to vigor or are some compensatory changes that maintain vigor? Why do different age-correlated functions seem to change at different rates in a single individual as it ages? Should aging be considered as a single, integrated process across the scales of biological resolution, from organismal to molecular, or must we consider each level of biological scale as a separate, distinct entity? Viewing aging from these differing perspectives yields distinct but comple-mentary interpretations about the properties and mechanisms of aging and may offer a path through the com-plexities related to understanding the nature of aging.

Automated summary

By asking questions about the nature of aging and examining data from Drosophila melanogaster, this study explores the complex interactions among age-related phenotypes at different biological levels. The differing perspectives on aging shed light on its properties and mechanisms, offering potential paths for understanding the nature of aging.