By Catherine Taylor
It’s a scene straight out of Gattaca — the 1997 futuristic film in which eugenics is used to breed and select American astronauts.
Ethan Hawke plays Vincent, a wannabe space explorer who’s held back by the fact he was born the “natural” way and not from a test tube. He’s managed to be shortlisted for an expedition to Saturn’s moon Titan, using someone else’s DNA to rort the system.
A machine beeps as Vincent’s stolen sample is processed. “Congratulations,” a doctor says.
“But, what about the interview?” Vincent stutters.
“That was it,” the doctor replies.
Could it soon be the same for elite athletes, chosen after years of hard work and passion, but selected from birth by the makeup of their genes?
Chinese swimming star Sun Yang says his doping days are over, but perhaps there’s a different performance advantage coursing through his veins: a “gene for speed”.
Last year, China’s Ministry of Science and Technology announced it would scour athletes’ blood for so-called “Olympic genes”, quirks of DNA that could deliver a natural performance advantage in the pool, or on the track.
Scientists have identified dozens of genes that are believed to control up to 50 per cent of athletic ability.
Professor Nir Eynon, an expert in genetics, epigenetics and sport, from Victoria University, says the genes help to explain why an average person could never outrun an Olympic sprinter like Usain Bolt, even if they trained alongside him for a decade.
“We have a limit, a cap, and we can’t perform beyond it. But people like Bolt have higher limits and there is a genetic question there [over what causes it],” he says.
Genetic researchers are slowly piecing together an answer to that question.
The way certain genes are expressed in the body can influence an athlete’s strength or endurance, making them better suited to sprinting or to marathons, for example.
This knowledge has raised yet more questions, ethical ones: should potential Olympians have their genome sequenced as a way of identifying talent or directing athletes into the sport they were, quite literally, born to play?
China thinks so. The Ministry said all Chinese athletes competing in the 2022 Winter Olympics would be selected after undergoing “complete genome sequencing” to test athletes for “speed, endurance and explosive force”.
Testing is believed to be underway by Beijing company Jiaxue Gene and will be completed next year.
The code for champions
To find these Olympic genes, genetic scientists must sift through a staggering number of variations in the human genome: around 3 billion letters of nucleic acid sequences, 38 million different potential sites of gene variation within 21,000 human genes, and 1,000 gene expressions known so far to be involved in determining the genetic component of things like height, weight or sporting ability.
Two genes that have most impressed scientists are the angiotensin-converting enzyme (ACE) and alpha-actinin-3 (ACTN3), a molecular protein.
ACE was discovered in 1998 by scientists at University College London and found to influence blood pressure and blood oxygen.
The way ACTN3 affects muscles was first explained by Professor Kathryn North, an Australian clinical geneticist and now director of the Murdoch Children’s Foundation, as part of her research into muscular dystrophy.
In the simplest of terms, all humans have the ACTN3 gene, but depending on the way it is expressed in the body muscles are categorised as “fast-twitch” or “slow-twitch”.
Fast-twitch muscles are capable of bursts of power, excellent for sprinting or short-distance swimming for example. This is the “explosive force” the Chinese are looking for when mapping the genome of athletes.
Slow twitchers are the endurance athletes: marathon runners or long-distance swimmers.
Combine that with the right expression of ACE to keep blood oxygen levels pumping and, well, you can imagine how the right genes might supercharge a human athlete.
‘Big bang of body types’
Professor Moran says that as athletes rise through international rankings it is reasonable to assume those with DNA that delivers sporting ability will be naturally selected so that at the highest levels of sport, most athletes also have a higher proportion of gene variants associated with sporting talent.
Professor North’s research bears this out: she notes that Olympic sprint athletes are rarely deficient in ACTN3, which influences the development of powerful, fast-twitching muscles. And other studies show ACE is more common in endurance athletes or successful mountaineers.
This biological filtering process is not just hidden in the blood. We can see evolution at work in the changing bodies of top athletes.
David Epstein, author of the 2016 book The Sports Gene: Inside the Science of Extraordinary Athletic Performance, believes there has been a “big bang of body types” in which natural selection is changing the shape of elite sportspeople.
Female gymnasts are getting smaller, the arms of top boxers are getting longer while tennis players’ forearms are getting bigger, he says.
It’s more complicated than testing
Does this mean we should now identify champion athletes like we do Melbourne Cup winners and target sporting investment to those most likely to achieve a gold medal?
Athletic ability is a polygenetic trait, says Professor Moran.
“If an individual has genetic markers that say he or she will be a great sprinter and others that say they will be a great endurance athlete, which is likely to win out?” he says.
So far, nobody knows.
While the research is promising, both Professor Nyron and Professor Moran emphasise it is too early to follow China’s lead and attempt to select athletes based on DNA.
The topic seems to be sensitive even in China: a series of stories about the 2022 strategy that were published on Chinese websites last year have since been blocked from the internet.
Dr David Hughes, the chief medical officer at the Australian Institute of Sport, says the organisation does not support the genetic profiling of its athletes.
“The holy grail for some research groups would be to discover a particular [gene mutation] that reliably predicts great athletic endurance capacity, aerobic capacity or power capacity,” he says.
He believes a blood test cannot identify an Olympian and the science, as it stands, has “zero predictive power”.
A test alone can’t determine the future
Even if research does eventually explain precisely the way gene combinations deliver sporting skill those pesky ethical questions remain.
“In some ways it will be a sad day when that happens because some individuals and research groups will go scanning the population to identify people with this capacity,” says Dr Hughes.
Professor Eynon agrees:
“There’s a big concern that you will take 15-year-old children and determine their future by genetic testing,” he says.
“You can’t do that. Athleticism is influenced by environment and genetics.”
Uncertainty around how to use the research to date has not discouraged private companies marketing genetic tests that “go right to the edge of government regulation”, says Dr Hughes.
Dr Hughes says he has been approached to provide AIS athletes as research participants for these private organisations. Although the AIS has worked with scientists, including Kathryn North, the institute has refused approaches from private companies —believing they are about making money, not pursuing science.
“This area is poorly regulated. It relies on high-tech sales pitches and slick marketing that is unsupported by science,” Dr Hughes says.
Clubs can’t resist the allure
Yet it is not only China that has begun to explore the possibilities of testing their athletes’ blood.
In the US, clubs in the National Football League are testing the genome of players as a way to tailor fitness programs or injury recovery.
Dr Hughes is unimpressed. It is a “slippery slope” he says, with “shades of the supplements and injections scandals of 2013″ that leave genetic testing only a few steps away from the murky, and illegal, world of gene editing, the new frontier of sport doping.
Is it a type of gene doping?
Testing the genome is not gene doping, which Professor Moran describes as “gene therapy for people who don’t need it”.
But scientists and regulatory bodies like the World Anti-Doping Agency and Australian Sports Anti-Doping Authority are worried.
The road travelled by many a middle-aged working mum is full of obstacles and few obvious rewards, so running a half-marathon on a Sunday morning is nothing — and in a sense everything.
Gene editing using CRISPR technology is advancing at an unbelievable rate, is cheap and relatively easy, says Dr Hughes. “But it is in imprecise technology. Even in the most capable hands it doesn’t always work and can lead to unexpected outcomes such as tumours or an immune system crash that can be disastrous,” he says.
Doping agencies including the WADA and ASADA are concerned enough to ban all forms of gene editing from 2018, which is much harder to detect than doping with drugs.
Athletes need to have a baseline genome sequence made so that any changes are evident.
For now, diet and training are the best ways for elite athletes to gain a (legal) competitive advantage.
But the right mindset “will never be irrelevant”, Dr Hughes says.
“Human performance is about having the right fitness, the right genetic material, but also the right frame of mind.
“Let’s not forget the placebo effect as well,” says Professor Eynon.
“If good athletes are told they have the right gene sequence and they are told every day this means they could win a gold medal then they may believe it. They may work harder. And that is what may make the difference.”