'Selection shadow' may explain why longer lives bring more age-related disease

Key Points:

• A new review in Nature Reviews Genetics integrates evolutionary theory, genomics, and human genetics to explain aging, highlighting how natural selection optimized biological pathways for youth but not late life, leading to aging and age-related diseases.
• Aging results from genetic mechanisms like mutation accumulation and antagonistic pleiotropy, combined with trade-offs in energy allocation between reproduction and body maintenance, which vary across species and individuals.
• Modern human societies, characterized by longer lifespans, lower birth rates, and improved medical care, reveal the late-life consequences of evolutionary "selection shadow," where harmful mutations and youth-optimized pathways affect many more people than in the past.
• Aging involves conserved molecular processes—such as DNA damage, mitochondrial decline, and altered signaling pathways—that underlie multiple age-related diseases, suggesting that targeting these ancient pathways could mitigate several conditions simultaneously.
• The review proposes an integrative framework linking evolutionary biology, molecular aging, and demographic changes, emphasizing that aging is shaped by both biology and social developments, and that future research should explore how demographic shifts impact aging mechanisms and healthspan.