Science Fiction Writer
ROBERT J. SAWYER
Hugo and Nebula Winner

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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.

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 accelerated aging.

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 she died.

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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