Scientific article for use with Question 7
Muscles, genes and gym in a bottle
A TENSE HUSH falls on the Olympic stadium as the sprinters crouch on the starting blocks for the
men’s 100-metres final. With the 2012 Olympic games in full swing, athletes have shattered records
as never before, usually by an ample margin. Television ratings are soaring, and as the finalists
prepare to compete for the title of world’s fastest man, the crowd expects the winner to obliterate
this record, too.
Though the Olympic flame still burns in the stadium, these athletes are nothing like their heroic
predecessors. Athletes of old honed their bodies with toil and sweat, but at the 2012 games most
of the champions have altered their genes to help them excel at their sport. Weightlifters’ arms
and sprinters’ thighs bulge as never before, and long-distance runners have unparalleled stamina
– all the result of a few crucial genetic upgrades. Officials are well aware that such “gene doping” is
going on, but as the practice is virtually undetectable, they are powerless to stop it.
This may sound like the ultimate sporting nightmare, but the technology to make it come true could
well arrive even before 2012. Scientists around the world are working to perfect gene therapies to
treat genetic diseases. Soon, unscrupulous athletes may be able to use them to re-engineer their
bodies for better performance.
Need more endurance? Add a gene to bolster delivery of oxygen to labouring tissues. Want
bigger muscles? Inject them with a gene that will make them grow. Both techniques are under
development, and if they work in humans as they do in lab animals, they will change the face of
nearly every sport. But at what cost? Knowing how to boost performance is one thing; knowing
how to do it safely is quite another. If athletes do turn to gene therapy, these genetically enhanced
champions risk paying for their success with heart disease, strokes and early death.
Genes matter when it comes to sport. At the 1964 Winter Olympics in Innsbruck, for example,
Finnish sportsman Eero Mäntyranta won two gold medals in cross-country skiing. Though his
training programme wasn’t radically different from those of his teammates and rivals, Mäntyranta
had a distinct advantage: he was born with a genetic mutation that loaded his blood with 25 to 50
per cent more red blood cells than the average man’s. Since these cells shuttle oxygen from the
lungs to the body tissues, Mäntyranta’s muscles got more of the oxygen they needed for aerobic
exercise, so he could ski faster for longer.
Mäntyranta got his extra red blood cells because of a mutation in the gene that produces the
receptor for the hormone erythropoietin (epo). The kidneys normally churn out epo when oxygen
levels in the body’s tissues drop, as they do at high altitude, where the air is thin. Epo commands
the body to manufacture new red cells, which raises…