Re: Cornering the causes of aging

From: Damien Broderick (d.broderick@english.unimelb.edu.au)
Date: Sun Jul 09 2000 - 20:23:04 MDT


At 03:49 PM 9/07/00 -0400, John K Clark wrote:

>A bug will probably get eaten within a year anyway so there's
>little point in maintaining the organism so well it could live longer than
that, better to reduce
>the maintenance budget and increase the reproduction budget and have lots
of offspring.

I keep reading this strange argument, but I can't understand why. Unless
you factor in some advantages from sexual re-mixing of
immunity/anti-parasite armaments, this mostly makes no sense to me (with
one exception, below).

*Everyone* has a chance of getting eaten within a given year, or a day. The
young are, if anything, *more vulnerable*.

On one hand you have a critter that's roughly as good as any other critter
of its kind, including its own offspring (which, after all, resemble it
quite closely). If it remains fertile and healthy, it is as fine an
instance of its kind as any of its kids. What's more, due to its history of
learning it's *better* - unless it has learned the wrong things, but is
error more hazardous than blind trial and error in the utterly ignorant or
gene-programmed? It's also bigger and stronger.

On the other hand, you have a swarm of spawn, innocent, comparatively
frail, but with their cellular clocks reset and their bods therefore
lacking the damage due to an accumulation of insults and injuries. This
method might bypass any need for specialised maintenance machinery outside
the germ cells, and since offspring are more numerous (usually) than their
progenitors they might have more chance of surviving random predation.
However, the triage rates among offspring suggest that this is not
necessarily a superior path. I'd go for just plain surviving, and getting
big and canny about your environment and enemies.

So there's no obvious advantage, to the embodied gene complex, in disposing
of a trained, fertile soma - *unless* the costs of maintaining its numerous
and specialised tissues are very much greater than throwing an adult soma
away and starting with ignorant near-copies with the key benefit of a
re-set self-repairing phase.

It seems to come back to the issue of disseminated maintenance mechanisms.
And if they don't exist in nature, we'll have to develop them, along the
lines of Freitas's suggestions with hard nanogadgets or maybe using
synthetic chromosomes packed with repair kits - which, sadly for us, would
most easily be introduced into embryos rather than decaying adults...

Damien Broderick



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