X-Message-Number: 12863
From: Thomas Donaldson <>
Subject: more about evolution of lifespan, a bit about DNA
Date: Sun, 28 Nov 1999 12:32:54 +1100 (EST)

For references about how evolution works, I've already given them but here
they are again, for those who did not take them down the last time:

GC Williams, "Pleiotropy, natural selection, and the evolution of
senescence", EVOLUTION 11(1957) 398-411

WD Hamilton, "The moulding of senescence by natural selection", JOURNAL OF
THEORETICAL BIOLOGY 12(1966) 12-45

JM Emlen, "Age specificity and ecological theory", ECOLOGY 51(4)(1970)
588-601

Yes, these references are all in the past. That does not make them less
pertinent or correct. GC Williams is the only author listed above who
does not use lots of math; instead he just uses logical argument.

So far (1999) these ideas have not been seriously challenged by anyone.
Various speakers have claimed that on some special cases evolution would
work to promote a group rather than an individual's genes. Yes, there are
very special circumstances in which that might happen, but they are 
sufficiently unusual that they can be ignored.

Why do these ideas suggest that evolution will make us actually live
longer (after generations, unfortunately): because most human beings alive
now are living well past the time stone-age human beings would be almost
all dead. This means that mutations promoting successful life early in
life but acting against success life later will face selection against
them. The same is true for any genes causing the loss of health that
goes with aging. It is very important here to realize that historically,
we live in an unusual situation, with many more people living to old
age than ever before. Even at the beginning of the 19th Century, most
people died about age 50... though a small minority, mainly upper class, 
lived longer. Since in all human societies, different classes interbreed
a lot, the presence of an upper class which lived a bit longer did not
affect the average lifespan at all.

The above is MY interpretation of the work of the three evolutionary 
theorists I list above. I do not know of any other source. But as you
can see if you read them, I'm not stretching anything they've said. If you
get interested, you might search out the GC Williams article and read it.

About DNA: Yes, in special circumstances DNA is durable. That's the point
of freezing; we can also find durability of it's protected from oxidation.
But so far as I know, DNA alone is NOT especially durable at all. I've
read references on this subject, but would have to search them up. If you
insist I'll get around to doing that.

			Best and long long life for all,

				Thomas Donaldson

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