Antagonistic Pleiotropy

What it proposes

George Williams in 1957 argued that aging is the price paid for genetic trade-offs. A gene variant that increases early-life reproductive success can rise in frequency even if it harms the organism later in life, because selection’s power on late-life fitness is much weaker.

Classic example: high androgen signalling promotes early reproductive success in males but contributes to late-life prostate disease.

The mTOR illustration

mTORC1 drives growth, anabolism, and immune competence — clearly beneficial early. The same activity sustained for decades drives metabolic disease, cancer, and (per multiple animal studies) shorter lifespan. Aging-relevant interventions that suppress mTORC1 (rapamycin, caloric restriction) make sense in this frame: they don’t fight evolved biology, they undo a trade-off that no longer pays off.

Implications

• Many of the “hallmarks of aging” are not bugs but features that became costly in long-lived organisms.
• Interventions that mimic ancestral stress conditions (exercise, hormesis, intermittent food scarcity) may restore a balance the modern environment disrupted.
• Selection pressure beyond reproductive age is weak; this puts a fundamental evolutionary brake on the longevity of complex organisms.

Related entries

Disposable soma, Hyperfunction theory, mTOR.