Crossing the Line: reading informational text; The ACTN3 Gene 8

Power Sports and the ACTN3 Gene

1. Genetics is a fast-moving field of science; as each year passes, scientists learn more and more about how different traits and physical characteristics are passed down from generation to generation. We know genes play a role in influencing certain sporting abilities—so will the day ever come when elite athletes compete separately based on inherited ability? It may sound far-fetched, but we already use categories of physical difference to decide who competes with whom: age groups, men’s and women’s events, boxing and wrestling weights, and the Paralympics and the Olympic Games. What makes genes different?
2. Let’s take a look at one particular gene as an example: the ACTN3 gene, sometimes known as “the gene for speed”, or “the muscle power gene”. There’s an increasing body of evidence indicating that certain variants of ACTN3 help to give people innate physical advantages in power sports: those that involve sprinting, throwing, or jumping.
3. These advantageous ACTN3 variants trigger the production of a protein called alpha-actinin-3, which fuels your fast-twitch muscle fibers. This can give your muscles really explosive power—the kind of power you need to win a gold medal in the 100 meters, javelin, or long jump, for example. And, sure enough, studies so far have shown that most elite sprinters, jumpers, and throwers have one of the ACTN3 variants that makes alpha-actinin-3. Some studies have also found a link between the same ACTN3 variants and stronger responses to muscle training, as well as reduced injury risk.
4. So if you have one of the “power” variants of ACTN3, are you guaranteed the fast-track to sporting glory? That’s what some parents hoped when ACTN3 first hit the headlines back in the early 2000s. And some companies jumped at the chance to meet that demand with ACTN3 genetic tests. Kevin Reilly, president of testing company Atlas Sports Genetics warned, “If you wait until high school or college to find out if you have a good athlete on your hands, by then it will be too late.”
5. Since then, experts have spread the word that tests like these don’t carry a lot of legitimacy. Geneticist Kevin Macarthur clarifies that “Most studies performed so far suggest that ACTN3 explains just 2-3% of the variation in muscle function in the general population.” More bluntly, he also states that “ACTN3 doesn't tell you whether or not your child will be a superathlete.”
6. A 2-3% variation in muscle function isn’t zero, but it is small; the amount of time and effort the average recreational athlete puts into their training and preparation will always be a much more significant factor than what’s in their genes. But once athletes get near the elite level, that’s when that 2-3% variation could make a real difference: between, say, those who make it to the finals of the national trials, and those who ultimately qualify for the Olympics.
7. So let’s circle back to where we started: as we gain greater insight into the relationship between genetics and sporting performance, how might that change the way we think about athletes and fairness in sports? Will we start hearing from proponents of separate sprinting events for athletes with “power” genes and those without? Will people advocate for allowing “genetically disadvantaged” athletes to take performance-enhancing drugs to level the playing field? Or even the reverse: should we disadvantage genetically-advantaged athletes to make competition more equitable? It’s all speculation based on what we know today, but strange things can happen in the world of sports.

Practice questions

Part A

Part B