Age-specific effects of deletions: implications for aging theories.

This article investigates the age-specific effects of genomic deletions in *Drosophila melanogaster* to better understand the genetic basis of aging and its evolutionary theories. The study finds that most deletions exhibit deleterious effects that worsen progressively with age, supporting a model termed "Increasing Effects Mutation Accumulation" (Increasing Effects MA), where mutations start as mildly harmful and become more detrimental later in life. While some deletions show patterns consistent with antagonistic pleiotropy (AP)—beneficial early-life effects followed by late-life harm—the majority do not fit classical mutation accumulation (MA) or AP models. These findings suggest that mutations with increasing negative effects across the lifespan may be a significant source of aging, highlighting the complexity of genetic contributions to senescence beyond traditional theories.