Athletic Ability and Genes

Athletic ability often appears to run in families. Some children seem to be born athletes while others do not perform well. New genetic research supports these observations, and has shown that there truly are athletic genes.

Body Type and Athletic Ability

Basic body type is something that is determined genetically. Studies have shown that different body types are associated with ability to perform in various sports.

• People who are taller and larger are more likely to excel at sports such as rowing and swimming. Their larger muscles allow them to use more oxygen, which gives them greater power.
• Smaller people have the advantage in sports such as cycling or running where they have to move their entire body weight over a distance.

The ACTN3 Genotype

Quick muscle reaction time is crucial for top performance in sprinting, martial arts and other sports where speed is emphasized. The ACTN3 gene has been found to correlate with fast-twitch muscle response. This gene produces the protein alpha-actinin 3 which is involved in enabling skeletal muscles to contract quickly and with force.

Everyone has two copies of ACTN3. It is the presence or absence of a variant gene within ACTN3, known as R577X, which seems to determine the way our muscles will respond. R577X stops developing muscle cells from being able to read the entire ACTN3 code and produce alpha-actinin-3.

• Those who do not have the variant gene R577X in either of their ACTN3 copies produce plenty of alpha-actinin-3 and may experience superior fast-twitch response. These athletes often excel at sprinting and other explosive, power-based sports.
• Athletes who have two copies of R577X use a different gene, ACTN2 for their muscles to work properly, since their ACTN3 genes are unable to produce alpha-actinin-3 protein. This genetic profile is common in elite endurance athletes who participate in sports such as cross-country skiing, distance running/swimming and rowing.
• Some people have a copy of R577X on only one of their ACTN3 genes. This genetic combination still seems to provide some advantage to female athletes in sprint/power events. Research on female athletes has shown that this pattern is more common in elite level sprint/power competitors and less common in those who excel in endurance activities.

Genetic Technologies, a company based in Melbourne, Australia is the first to offer a test for R577X which is available to the public. The test involves collecting a genetic sample from the inside of the cheek, and mailing it back to the Melbourne lab. The cost of their Sports Gene Test is $110. The company cautions that many factors contribute to athletic performance including:

• coaching and training programs
• diet
• environment
• genetics
• psychology.

A Sports Gene test can help an athlete determine the type of sport in which he or she is most likely to excel.

The ApoE4 Gene

Some sports, such as boxing, carry a high risk of head injury. Research has shown that people with the e4 variation of the ApoE gene have been found to have a poorer recovery after injuries to the head. The government of Australia is taking this so seriously, that they are considering mandatory genetic testing for boxers to see if they carry the ApoE4 gene.

Testing for ApoE4 can potentially protect many people. Those who carry the gene may choose not to participate in sports likely to lead to head injuries. This could preserve the health and quality of life for countless athletes. Unfortunately, the ApoE4 gene variant is also associated with the development of Alzheimer's disease. Athletes considering genetic testing for this gene may want to think about how their lives would be affected by finding out they are at higher risk for this devastating illness.

Controversies

Genetic testing for athletic ability may help young athletes choose a path, and it opens up many exciting possibilities in the athletic field. Children found to have athletic genes may be at an advantage if their training begins early in life. However, athletic genetic testing does also raise some serious concerns, including:

• emotional consequences of discovering associated disease risk
• loss of interest in exercise leading to poor health for those found not to have athletic genes
• parents attempting to "design" babies with athletic aptitude.
• possible exclusion from sports teams and competitions for those with unfavorable genetic profiles.

Resources

Berkich, D. (n.d.). Genetic testing for athleticism. Retrieved September 16, 2008, from the Global Ethics Consortium Web site: http://gec.tamucc.edu/article.pl?sid=07/10/28/179211.

Genetics Technologies Limited Staff. (2006). Frequently asked questions. Retrieved September 16, 2008, from the Genetics Technologies Limited Web site: http://www.gtg.com.au/humandnatesting/index.asp?menuid=070.110.050#3.

Kolata, G. (2007). Bigger is better, except when it's not. Retrieved September 16, 2008, from The New York Times Web site: http://www.nytimes.com/2007/09/27/health/nutrition/27Best.html_r=2