Tim Radford
A heredity that helps some mountaineers breathe easily at Everest heights and keeps young soldiers at peak fitness could soon answer questions about heart disease and stroke.
A team of British scientists revealed last week that in life’s genetic poker game, they may have identified the Ace hand for athletes. Ace stands for angiotensin-converting enzyme. It is one of the proteins that influences the uptake of blood and oxygen in the cell. The gene that makes it exists in two forms known as I and D. Since everybody inherits a gene from each parent, some people have II, some have ID and some have DD versions.
Dr Hugh Montgomery and Professor Steve Humphries, two cardiovascular researchers at University College in London, and colleagues, report in Nature that people with the II version seem remarkably better equipped for endurance training.
They sampled the DNA of a small elite of mountaineers who have climbed more than 7E000m without oxygen. One fourth of most Britons carry the DD version – but only 8% of the mountaineers.
The scientists also tested young soldiers during a 10-week fitness training programme – and found that those with one or more of the I versions of the gene showed improvements in weightlifting 11 times greater than those with the DD version.
They and the mountaineers were equipped with “lean burn” body machinery that made the most of what little oxygen there was.
“The recruits all had to do the same amount of work to get past their training period,” said Humphries. “In some of them, their hearts had to put on quite a lot of increased weight to do that. People who had the I version did not have to increase their heart size at all.”
The genetic deal, however, is not necessarily a winning hand for sportsmen. It may help endurance in extreme conditions, but it is not a substitute for co-ordination, acceleration or determination.
“Is this going to be the gene to select professional football players? If I was the club manager would I be selecting the England squad by genotype? The answer is definitively no,” said Montgomery. “We have not analysed professional footballers, but I would bet my next 10 years salary that it would be useless because there is far more than a very isolated measure of endurance involved in footballing.”
Nor is a gene for selecting army recruits. “It is not going to affect global physical performance,” he said.
But the knowledge could help answer questions about altitude sickness in mountaineers, and about blood pressure, heart damage and strokes, in which cell tissues are deprived of oxygen.
Some victims recover, others die from similar cardiovascular attacks. The betting is that the Ace gene is involved. There is already a useful class of drugs called Ace-inhibitors, used to treat high blood pressure.
“There are lots of situations in which heart or lung disease limits oxygen supply to the body,” said Montgomery, “or situations where the isolated organs like the brain or the heart suddenly get deprived of oxygen or nutrients. If we are right – it is a hunch and we don’t know yet – it is possible we could manipulate this system pharmacologically in order to allow cells to survive better in the presence of low oxygen delivery.”