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The Fountain of Youth
Copyright © 2003 by Robert J. Sawyer
All Rights Reserved.
Nebula Award-winning science-fiction writer
Robert J. Sawyer
writes and presents a weekly science column for
the Canadian Broadcasting Corporation's CBC Radio One.
The columns, which have the umbrella title
Science FACTION: Commentaries from the Cutting Edge of Science,
are produced by Barbara Saxberg in Toronto, and
syndicated to local CBC Radio stations across Canada.
Recorded 23 June 2003
Host: Living longer! It's been a human dream since the
dawn of time. And we're finally making some progress toward
achieving it. The Spanish explorer Ponce de Leon thought the
fountain of youth was on the island of Bimini but it turns
out it might be hiding within one of our oldest and deadliest
foes. Here's science-fiction writer Robert J. Sawyer, who plans
to live a long, long, long time ...
Robert J. Sawyer: You know those little doodads on the
ends of your shoelaces those things that Jerry Seinfeld
reminds us don't even have a name? Well, something very like them
may hold the key to human immortality.
Think of your chromosomes as shoelaces long strings of
DNA. At either end of them, there's a little protective cap.
Those caps do have names: they're called telomeres, which
is just Greek for "end segments."
Every time your chromosomes reproduce which they do each
time your cells divide the telomeres get a little shorter.
Eventually, you run out of them all together. And just as you can
no longer easily thread shoelaces once the plastic end cap is
gone, a chromosome without a telomere can no longer reproduce.
The fact that our chromosonal endcaps disappear over time is one
the key reasons we age: it means our cells lose the ability to
divide, and so eventually die. In fact, scientists call this
phenomenon "programmed cell death," because, like planned
obsolescence of a dishwasher or refrigerator, cells seem designed
to give up the ghost after a certain amount of time. Cells in
human bodies are limited to between 40 or 90 divisions the
count varies by cell type. After that, it's game over.
Indeed, in rare cases, humans actually grow old prematurely.
There's a disease called progeria; those poor unfortunates who
have it age rapidly, looking like senior citizens while still
children, and then they die an early death. Progeria sufferers
have much shorter telomeres than normal people; their cells die
much more quickly, and that apparently causes the abnormally
The same thing is happening with many animals that we've tried
cloning: because the source genetic material comes from an adult,
clones often age prematurely.
Sound Effect: Sheep bleating
Dolly, the cloned sheep, was made from DNA taken from a grown-up
female sheep's teat her name "Dolly" was actually a
tip-of-the-hat to singer Dolly Parton, famous for that particular
part of her own anatomy. But the unfortunate byproduct of making
Dolly from adult DNA was that she was born old and died
young. Dolly was put down at the age of six, about half of a
normal sheep's lifespan, because she'd contracted a kind of lung
disease common only in elderly sheep. She also had arthritis when
Music: Happy Birthday To You
But there is good news: a natural enzyme called telomerase causes
telomeres to regrow; it puts the end-caps back on the shoelaces
that are chromosomes. Tests have shown that normal human cells
treated with telomerase can go on reproducing indefinitely;
telomerase might quite literally be the fountain of youth.
Of course, there are other reasons why we age and die
wear-and-tear on joints and organs, heart attacks, Alzheimer's,
the oxidization of chemicals in our bodies. Telomerase doesn't
cure any of those, but, still, scientists are talking about being
able to easily extend the human lifespan to 120 years and
perhaps much longer with telomerase treatments.
Why did this programmed cell death evolve in the first place?
Well, some cancer cells naturally produce telomerase
that's what lets them go on dividing indefinitely, forming clumps
of tumor tissue. Our cells may have evolved their limited
lifetimes specifically to keep them from turning cancerous. The
ultimate irony is that now we're talking seriously about taking
the key weapon of one of humanity's worst foes telomerase
and turning it into the secret of longer life.
I'm Robert J. Sawyer.
More Good Reading
Other "Science FACTion" commentaries for CBC Radio
"2020 Vision" scenarios for Discovery Channel Canada
Media backgrounder on Rob Sawyer
Rob's novel Starplex, which deals with telomeres
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