Evolutionary theory has long held it impossible for there to be genes whose purpose is to limit how long we live, or to cause the familiar symptoms of deterioration with age — and it seems intuitively obvious that a gene contributing to the death or poor health of its owner ought to be opposed by natural selection. But now a new computer modeling study turns this idea on its head, showing that deliberate mortality can actually give an advantage in the long run.
The findings are described in a new Physical Review Letters paper authored by Wyss Institute Senior Research Scientist Justin Werfel, Ph.D., Wyss Institute Founding Director Donald Ingber, M.D., Ph.D., and New England Complex Systems Institute President Yaneer Bar-Yam, Ph.D.
The key to the mechanism behind the new results lies in how space is taken into account. Traditional theories rely on a hidden assumption that organisms in a population all experience the same environment. But in the paper, Werfel, Ingber and Bar-Yam show that in simulations of evolving systems spread out in space, where the distance organisms can travel is limited — as is typical in the real world — organisms that limit their own lifespan outcompete those that live longer. The way the simulated organisms use resources and shape their local environments gives the self-limiting ones an advantage that may only appear after many generations.
These results help provide a new explanation for observations in nature which the traditional theories have had trouble accounting for, and imply that genetic controls to tune lifespan are likely to exist and may be amenable to medical interventions that could extend healthy lifespans dramatically.