Gene test finds fast feet in cradle

LONDON - Sprinting champions could be selected at birth using a DNA test that searches for a particular gene which marks them out as "born to run."

The controversial idea follows the discovery by Australian scientists that almost all top sprinters, such as Linford Christie, have a specific form of a gene called alpha-actinin-3, or ACTN3.

The reverse was true for successful endurance athletes, implying a genetic role in their success.

Performing a genetic test for ACTN3 would be a simple process requiring only a swab from the mouth.

It opens up the potential of promising athletes being directed into sprinting or marathons from their earliest years - a prospect that gave sports heads pause.

Rodney Walker, chairman of UK Sport, which oversees sporting development in Britain, said: "Screening would only ever give an indication, albeit a potentially valuable one, as to a child's athletic promise."

He said he thought it should be up to society as a whole, rather than sporting bodies, to judge whether genetic screening was appropriate or desirable.

The discovery emerges from examination of the ACTN3 gene, which comes in two varieties.

The "R" version makes a protein called actinin that is found only in the "fast twitch" muscle fibres, which are essential to produce the explosive energy release needed by sprinters.

The unusual "X" version of ACTN3 does not make actinin-3.

About 20 per cent of the population has one or two copies of this form of the gene.

When the team at the Institute of Neuromuscular Research in Sydney examined the genetic makeup of more than 300 athletes, 50 of whom had represented Australia at Olympic or international level, they found that 95 per cent of the sprinters had at least one copy of the R gene and 50 per cent had two copies - one inherited from each parent.

"No female elite sprinters, and no sprint Olympians, were XX," the research leader, Professor Kathryn North, told New Scientist magazine, which published the results this week.

Among endurance athletes, 76 per cent had one R gene, and only 31 per cent had two copies - a significant difference from the sprinters.

But 24 per cent had the "XX" combination - notably larger than the 18 per cent in the general population.

There, 72 per cent had one copy of the R variety, and 30 per cent had two Rs.

Professor North said that actinin-3, the precise function of which is not known, might "confer a greater capacity for the absorption or transmission of force during rapid, forceful contraction."

The gene is the second known to confer athletic ability.

The first, angiotensin-converting enzyme (ACE), makes a protein which influences how well the muscles burn oxygen, and the rate at which some muscles grow. High-altitude mountaineers commonly have two copies of the most efficient form of ACE.

The role of ACE in exercise was discovered by Dr Hugh Montgomery and researchers at University College London, who claim to have evidence of a third gene that can enhance physical performance.

Dr Montgomery dismissed the notion of talent scouts screening infants to find future elite athletes.

"It's very unlikely there will be one gene that is a major indicator of performance," he said.

Many factors influenced sporting success, including body size, muscle fibre type, metabolic efficiency, lung volume, and psychological make-up.

Jason Gulbin, who co-ordinates scouting activities for Australia's Institute of Sport, said the idea of genetic profiling to determine future potential was "highly contentious."

But he added: "If we find a genetic profile has a useful predictive function, then I prefer to consider how this might be used to positively discriminate."

He said multi-talented athletes had only a short time in which to decide which area would suit them best.

Knowing their genetic make-up could help them make an informed choice about which discipline to focus on.

- INDEPENDENT