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Eternal youth? It's all in the genes
By DAMIEN BRODERICK Wednesday 19 April 2000 IN LATE February, Dr Ron DePinho and other scientists at the Dana-Farber Cancer Institute of Harvard Medical School and Albert Einstein College of Medicine reported that they had rejuvenated elderly mice. Using gene therapy techniques, they replaced a deleted gene in prematurely aged mice, which bounced back to youthful health. Would it be wrong to use such techniques to change aspects of our own genetic inheritance? Such anxiety is misplaced. Our cells are lashed by stray high-speed particles and disruptive chemicals, many from the natural foods we eat. To do better than nature, which kills us all at 120 or much earlier, we need an improved repair and maintenance system. DePinho's efforts are among the first successes in compiling a repair kit. The end result, expected by optimists to pay off within decades, should be a gradual extension of healthy lifespan. We won't fall sick as easily, and we'll recover from illness and accident more swiftly. Tissues won't deteriorate steadily just because years pass. Is it wicked or misguided to seek such a scientific cure to routine ageing? Human cells, tissues and organs lack a full maintenance program. Other animals are more fortunate. Lobsters and trout are protected against ageing by an enzyme, telomerase - although not against hungry fishermen. DePinho's genetically engineered mice entirely lack the gene for that same repair enzyme, and so are prey to various age-related illnesses, including chronic liver disease. The full human genome, our own genetic "recipe", has now been mapped. Within a few years, we'll learn exactly how it is expressed in proteins, and how those building blocks work alone and together. Then, inevitably, we'll start selectively rewriting the genetic coding of our bodies, repairing and even improving our legacy. Maybe we'll choose to import one or more artificial chromosomes loaded with useful upgrades. This is not far-fetched - such contrived strings of genes have already been inserted into experimental cells, with no harmful effects. Fresh information is arriving with breathtaking speed. The private US research effort, Celera, finished mapping the complete genome code months earlier than expected, and years before the huge Human Genome Project's own announced date. IBM is building a computer, Blue Gene, able to process 1000 trillion calculations a second, so it can model precisely how the proteins ordained by our DNA code fold up and interact. By 2005, we'll know a lot more about specific risks of inherited diseases. Will we use that knowledge to change our individual codes? Not in the immediate future. Too risky, too scary to people who get spooked by genetically modified food (which is actually pretty safe and offers important benefits). But we'll surely see very early scanning of pregnancies for a host of potential disorders, allowing parents to seek early termination and try again. Sounds like eugenics? Not in the vicious sense. Most Down syndrome foetuses, with a damaging three copies of chromosome 21, are aborted after early screening. Ethicist Nicholas Tonti-Filippini has warned on this page (March 23) that this approach might not be acceptable, creating a society intolerant of diversity. But should we prefer more retarded babies, more suffering people afflicted with spina bifida or cystic fibrosis? Won't clones be stored and rifled for spare parts? No. That's just a Hollywood horror story. Your clone is your twin. Would you callously demand your twin's heart or right hand? Would anyone let you have it? Instead, we'll use cloning technology to grow tissues or organs. Your own stem cells will be modified to form hearts, lungs - or teeth, replacing any lost through decay and wear. Adults may grow new teeth. Or teeth could be grown in a culture medium, perhaps at an accelerated rate and then implanted, using recently discovered angiogenesis factors to stimulate new blood vessels, and other growth factors that boost nerve connections. The key gene coding for a protein that grows local blood supply, sox18, has just been identified by researchers at the University of Queensland. Switching such genes off, by contrast, will starve cancers, allowing the immune system to deal with them. Babies born 30 years hence may grow up with such perfect cellular maintenance that they need never age, dying only by accident or choice. Will we get the benefits of these discoveries? Maybe not - we might be, sadly, the last mortal generation. But who knows - if we can keep ourselves alive and healthy, maybe some of these treatments will be retrofitted into our ailing bodies and make us new again, like DePinho's mice. Won't drastic life-extension methods be too costly for us ordinary folks, and instead be hoarded by the rich and renovated? At first, treatments may be very expensive. But not necessarily all. Today, antibiotics are inexpensive. Fresh water, sewerage, immunisation and antibiotics allow us to live longer and better. While these services cost a huge amount to install, everyone benefits, and the cost per person is fairly low. It could be the same with superlongevity treatments. If you're lucky you may see the year 3000, or even live indefinitely. We need to discuss, well ahead of time, whether that would be desirable. Me, I'm voting for life over death. Dr Damien Broderick's books include The Spike and The Last Mortal Generation. E-mail: [EMAIL PROTECTED] The Age, http://theage.com.au/news/20000419/A12020-2000Apr18.html |
