Hacking Evolution for Living Indefinitely
by Paras ChopraOur bodies have been designed to reproduce the genes to the next generation. So, after 50-60 years, when the reproductive phase ends, then the evolution doesn't have anything to do with us. Why should evolution prevent us from dying when we do nothing to pass on genes and in fact use up resources that can be used by other organisms for reproduction? That is the reason we die. After the reproductive phase, we do no good as far as preserving genes is concerned, so evolution lets others use the resources.
Let us imagine that we have a gene called TOTAL_AGE and another gene called REPRODUCTIVE_AGE. And now, if there is a mutation in TOTAL_AGE which shoots up the age to say 200 then REPRODUCTIVE_AGE being the same, won't make any difference to the fitness of an individual. That's because another individual with same REPRODUCTIVE_AGE but having TOTAL_AGE of 100 is equally like to produce as many offspring as the previous one. Thus, from an evolutionary point of view, they both are equally fit, hence no selection pressure.
But, on the other hand, if some mutation doubles the REPRODUCTIVE_AGE then this individual is considered fitter and he is more likely to be selected by the natural selection.
Hence, if we somehow, manage to increase the reproductive age of an animal, then in the long run, animals with longer life spans are likely to be selected. Experiments in this regard have already been carried out by Michael Rose on fruitflies. By selecting eggs from females at progressively later dates in their reproductive cycles, he was eventually able to breed flies that lived twice as long on average. And as a nice illustration of the coupling between age of reproduction and lifespan, these flies bred much later in life than normal flies.
One way to prevent natural death from aging is to keep reproducing indefinitely. This will certainly help evolution to select populations with larger life spans. Thus, in long term, we can increase the life span of humans. I don't know what restricts the humans to keep on reproducing, but if can be possible, then we might live indefinitely (well almost)...
April 2006, Jeev
http://www.dce.edu/jeev
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