DNA Test To Determine Kids' Sports Futures 240
bs0d3 writes "Parents are being sold on the idea of buying DNA tests for their kids, to find out which sports they will be better at. The company called Atlas is based in Boulder, Colorado; and is selling DNA tests for $160. They are looking for what's called the ACTN-three gene, the gene behind what is called 'fast-twitch explosive muscles.' Children that don't have ACTN-three will be better suited for endurance sports like long distance running or swimming. Children that have a lot of it will be better suited for sports like football, rugby, wrestling, or hockey. Kids that have some ACTN-three will not be the fastest and not the slowest, they don't burn out the quickest and they don't last the longest. They are categorized as capable of playing just about any type of sport they like."
Re:Cue the whining about modern society... (Score:5, Informative)
Because modest amounts of sequencing have gotten so cheap, tests of this flavor don't tend to be outright lies(they do, indeed, usually test precisely what they claim to test); but the sales pitch inevitably glosses over the fact that only a few phenotypic characteristics are actually wholly determined by the single gene they can economically sample for.
There are a few conditions that are sufficiently well understood, and causally simple, that you can actually get a "Yes/No" out of a genetic test; but they are rare, and this is unlikely to be one of them.
I'd certainly be delighted to see genetic defects avoided, and useful genetic traits made more commonly available, but I'm not impressed by the chances of opportunistic lab-coated fortune tellers being the ones who get us there...
Re:Even easier (Score:5, Informative)
Exactly. Much of Malcolm Gladwell's book, Outliers [gladwell.com], is devoted to explaining this principle. I put an article about it on my blog [blogspot.com] a while ago, but far more importantly, it's been on Cracked.com [cracked.com].
Better Way (Score:5, Informative)
OTOH, most people figure this out in childhood. Either you excel at sprinting, distance, or are mediocre at both. Plus, factors like body habitus play a greater effect than raw muscle composition, and practical experience is the only thing that factors everything in. But that's kinda irrelevant. Let the kid do what they like rather than push them into something they're most likely to win at. They'll probably wind-up picking their optimal sport anyway, and if their parents think the lost year or two of grade school training is a problem then there are some serious issues at hand.
Some more info re: the gene (Score:5, Informative)
Shameless (and copyvio) copy/paste from 23andMe [23andme.com]:
This gene produces a protein called alpha-actinin-3 that is only turned on in fast-twitch muscle fibers (the kind used for power events like sprinting or weightlifting). The protein forms part of the contractile machinery in muscle cells, where it is thought to play both structural and signalling roles.
The T version of the SNP in this gene prevents the full protein from being made. People with two copies of the T version thus have a total lack of alpha-actinin-3 in their fast-twitch muscle fibers. Those with the CT genotype have one functional copy of the gene and can still make the protein.
Surprisingly, a complete lack of the alpha-actinin-3 protein doesn't seem to cause any type of disease. This is probably because another closely related protein can step in for alpha-actinin-3 in people without a functional copy. The substitute protein likely does not perform its job as well as alpha-actinin-3, resulting in worse performance in power exercises.
Despite lack of a disease outcome, researchers wondered if the absence of alpha-actinin-3 might have an effect on athletic performance. Studies of elite athletes in Australia and Finland showed that power athletes—those whose performance depends on fast-twitch muscle fibers—were much more likely to have at least one working copy of the gene than non-athletes. In one study of Olympic power athletes (i.e., the best of the best), all had at least one working copy. Similar results were found in a study of Spanish professional soccer players.
But does alpha-actinin-3 make a difference for non-athletes? In fact, it does.
One study looked at a group of Greek teenagers who had been tested for a variety of fitness measures related to power and endurance sports. In this group, ACTN3 genotype had no effect on the girls, but boys with the TT genotype were significantly slower in a 40 m sprint. Interestingly, running was the only power event that the different versions of ACTN3 seemed to affect. For activities like throwing a basketball or jumping into the air, performance was unaffected by genotype.
Another study looked at arm strength in a group of people before and after 12 weeks of strength training. ACTN3 genotype appeared to have no effect in men, but women with the TT genotype had lower strength at the beginning of the study. After the training program women with the TT genotype—those without a working copy of alpha-actinin-3—had made greater gains than the women with at least one functioning copy. This was true in both European and Asian women.
Scientists aren't really sure why having alpha-actinin-3 would improve power performance. One theory is that the protein prevents damage in fast-twitch muscle fibers. The group who conducted the study of Greek teenagers thinks this explains why only running and not other power activities were affected by a lack of alpha-actinin-3. Running involves repeated use of the muscles, while jumping only uses muscles once: damage is not an issue.
The scientists who saw that women with the TT genotype were able to build up more strength than other women also think alpha-actinin-3 protects muscle fibers from damage. Muscle damage is what stimulates muscles to adapt and become stronger. Those with the TT genotype lack the protection against damage that alpha-actinin-3 normally provides, thus allowing a greater gain in strength.
Alpha-actinin-3 may also affect athletic performance by virtue of its effects on oxygen usage in muscle. Two studies (one in mice and one in humans) have shown that fast-twtich muscle fibers that lack functional copies of ACTN3 use more oxygen than those with at least one working copy. This type of metabolism might slow them down. Mice studies have also shown that these altered fibers are weaker and smaller than fibers containing alpha-actinin-3, but they are more efficient an resistant to fatigue—a situation that is better suited to endurance sports than sprinting.