for National Geographic News
Although athletes at the Beijing Olympics have been subjected to some of the most aggressive testing ever for performance-enhancing drugs, no case of so-called gene doping has yet been detected.
But experts say Oympic athletes may soon be able to genetically enhance their muscles to be faster, stronger, and better able to recover after workouts—if they aren't already.
Gene doping uses techniques similar to gene therapies developed to treat muscle-wasting diseases, such as muscular dystrophy.
Injected into an athlete, a harmless virus could carry a performance-enhancing gene and splice it into a muscle cell, said Theodore Friedmann, a gene therapy researcher at the University of California, San Diego (quick genetics overview).
A synthetic virus called Repoxygen, for example, has been used this way in animal tests to insert a gene for erythropoietin (EPO), a hormone that tells the body to make more red blood cells, which carry oxygen to muscles.
EPO is important in the treatment of anemia, and it's also a favorite doping agent for cyclists, runners, and cross-country skiers.
Athletes are well aware of Repoxygen's potential: A German coach was accused of trying to obtain it before the 2006 Winter Olympics.
Gene-doping may also work by modifying genes that are already in an athlete's cells but whose functioning he or she might want to control.
It's not a new concept. Many ordinary drugs can have this effect, as can daily activities.
"Training and athletic workouts probably do their work at least partly by modifying the expression of genes," Friedmann said.
A few years ago it was believed that wholesale gene doping was just around the corner. But clinical trials of legitimate gene-therapy methods have run into hitches.
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