Where are the perfect repair systems?

Jurgen Kaljuvee kaljuvee at HUSC.HARVARD.EDU
Sat Feb 1 21:35:04 EST 1997

On Sat, 1 Feb 1997, Nicholas Migliozzi wrote:

> Hi.
> What is the latest on anti-aging research?
> Can it really be that aging is caused by genetics?
> If so, why does aging affect people in so many different ways?
> No two old people suffer in the same way from old age.
> Some live to 100.  Others die at 60.  Isn't this strange?
> I rather think that old age is "wear and tear".
> A car gets old too, and certainly genetics is not to 
> blame here.  
> Perhaps people get old in the same way that a car gets old.
> What do scientists have against this theory?  It is reasonable,
> isn't it?  Old cars.  Old people.  The same wear and tear.
> Thanks in advance,
> Nicholas

People and cells are self-repairing systems, cars are not (any molecular
biology textbook will describe several repair systems for both DNA and
cytoplastic components).  Another way of saying this is that cells and
people use the energy of the environment (food) for not only movement (as
cars do) but also  to maintain, with the help of repair systems among
other things, something called cellular homeostasis
(equilibrium roughly speaking). If the repair systems were
perfect, which  they are not unfortunately, if all the damage and "wear
and tear" were repaired perfectly, we could go on living much longer.

A natural question arises: "If evolution has developed everything
imaginable, why hasn't it developed perfect repair systems?"

To answer the question, consider the following thought experiment.
Suppose that several million years ago there was a species of, say, fish 
that developed a perfect repair systems and as a result couls achieve a
lifespan that extended to several hundred or even thousands of years.
If so, why don't we see the species today?  Where did it disappear? The
answer is that by attaining perfect repair system, the species lost the
capacity for mutation and variation and consequently for evolution. It
was soon outcompeted by a species which, though mortal on the individual
level, carried superior mutations as a species.  Evolution presumes
variance, selection and mortality.

So if human species developed perfect repair systems, not through
evolution, but artificially in a lab (as we have done so much else) would
it mean the end of species? Maybe in the long run, say in few thousands
years, when we would be outcompeted by apes with superior mutations (IQ =
250) but that's not my top concern right now as my clock is ticking
minutes and hours, not in thousands of years...


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