It may not be long before we see the first genetically modified athlete, some say. Others fear the use of gene therapy to improve athleticism is already a reality. But since sports authorities' testing methods still lack the sophistication needed to pick up "gene doping," its status remains unclear.
What is certain is that it is technically feasible to use genetic modification to improve sporting performance, in animals at least, and that some athletes are prepared to risk their lives if they could be guaranteed gold medals.
UK Anti-Doping, the body which oversees the control of performance enhancing drugs in Britain, says genetic manipulation as a form of performance enhancement "is currently a theoretical rather than a proven issue."
But Andy Parkinson, UKAD's chief executive said: "I wouldn't be surprised if someone out there is trying to do it, and I think that's very worrying."
The World Anti-Doping Agency (WADA) says it is ploughing "significant" money and resources into research into finding ways to detect genetic enhancement of athletes.
'Unlikely gene doping is happening now'
Chris Cooper, a professor of sports and exercise science at Essex University and author of a book called "Run, Swim, Throw, Cheat," thinks it is "hugely unlikely anyone is gene doping" and says the focus should be on people who use well-known performance enhancers like anabolic steroids and blood doping.
However, e-mails that surfaced during a trial of a German track and field coach Thomas Springstein in 2006 showed that people behind some athletes were at least thinking about genetic modification as a way forward.
The drug mentioned in the 2006 German court case was Repoxygen - a gene therapy developed by the British biotech Oxford Biomedica as a treatment for severe anaemia. Repoxygen is based on a direct intramuscular injection of an inactivated virus carrying the gene for erythropoietin -- beloved by athletic dopers seeking to artificially boost their red blood cells and aerobic capacity.
In an e-mail written to a Dutch doctor, coach Springstein wrote, "New Repoxygen is hard to get. Please give me new instructions soon so that I can order the product before Christmas." Scientists developing gene therapy techniques in laboratory animals have also reported being inundated with inquiries from sports people keen to know more.
Super mice studied
Lee Sweeney, a professor at the University of Pennsylvania in the United States, has pioneered research into gene transfer technology and developed various super-sporty lab mice to test its potential.
In 2007, while researching possible ways to restore muscle growth in patients with muscular dystrophy, Sweeney and his colleagues created mice who continued to have enormous muscles and significant strength into old age.
The super mice were created by injecting normal mice with a virus containing the gene for insulin growth factor 1, which interacts with cells on the outside of muscle fibres and makes them grow.
They were nicknamed "Schwarzenegger mice" after the American bodybuilder and film star-turned politician. Scientists later reported success in treating dogs with wasted muscles with the same therapy.
A few years earlier, "marathon mice" hit the headlines after researchers genetically engineered the lab animals by tweaking a gene called PPAR-delta. The genetically modified mice could run twice as far as normal mice, and they stayed lean even when they were fed a high-fat diet.
In his book, Cooper tells of an experiment by Jim Wilson, one of Sweeney's colleagues at the University of Pennsylvania, using EPO gene therapy in macaque monkeys.
It initially worked as expected, increasing oxygen transport in the monkeys' blood. But the high concentrations of EPO soon produced so many red blood cells that the blood became like sludge and needed to be thinned at regular intervals.
Then the monkeys' EPO levels suddenly plummeted, leading to severe anaemia and forcing the scientists to end the experiment and euthanize the animals.
Yet would-be genetically modified Olympians may regard the risks of gene doping as worthwhile.
Athletes wiling to risk health
In a frequently-cited survey, Dr Bob Goldman, founder of the U.S. National Academy of Sports Medicine, asked elite athletes in the 1980s whether they would take an enhancement which guaranteed them gold medals but would also kill them within five years. More than half said yes.
"I was shocked to see that out of 198 world-class athletes, 52% would be willing to give up their life for five years of an undefeated run of wins," Dr Goldman said during the 2004 Olympic Games in Athens.
He repeated the survey every two years for the next decade and the results were always the same - around half of the athletes polled were ready to die for gold. "Some of the athletes are only 16-years-old," Dr Goldman said. "To be willing to die at 21 is a serious psychological mindset."
While no-one can be sure if genetically modified Olympians are swimming in pools or running on tracks right now, the lure of winning gold may make athletes more willing than most to take a dangerous genetic leap into the unknown.
"That's partly why the world of sport is so concerned," said Andy Miah, a bioethicist and director of the Creative Futures Institute at the University of the West of Scotland. "They know that if athletes had something that would give them the opportunity to win medals, but would kill them 5 years later, many of them would take it.
"This is a community of high risk takers."
(Reuters Health, August 2012)
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