In his Science Fiction novel Methuselah’s Children, Robert Heinlein described a clan whose members become unusually old without showing signs of frailty. They arrived there by selective breeding for old age.
What would it take to actually breed a population to maximize its life span? Doing this in humans isn’t going to happen outside of sci fi stories, but it may be feasible for mice or other model organisms. Selective breeding can achieve astounding results in just a few generations. The domestication of foxes from wild to tame famously only took a few decades.
The obvious model organism to try this with is mice. To my knowledge, while there have been pilot experiments, this hasn’t been attempted over the long term. It’d take a long time and it’d not be cheap. To ensure enough genetic diversity for selection to take place, you’d want to start with at least 1,000 individuals. If you pick the longest lived 10% each generation, getting to 10 generations would cost $4 million. The experiment would take around 12 years. That’s because even though the high end of mouse life expectancy is around 3 years, the next generation can be bred up without having to wait for most of them to die first.
It’s impossible to tell what kind of increase to expect. Anything from 10% to 100% is plausible. By looking at other model organisms and the mouse pilot experiments in more detail, it’d be possible to refine that estimate.
The data would be helpful for the ageing research field. Comparing generation 1 and generation 10 would point to genetic changes associated with lifespan, but it’d also point to “free rider” traits that unintentionally get selected when maximizing lifespan. For example, is generation 10 smaller or less fertile than generation 1? Antagonistic pleiotropy suggests we will see a lot of this.
Nehaveigur 