Were You Born To Be An Athlete? Know Your Sport Genes

Human physical capability is influenced by many genetic factors.

In the recent years growing research and development of technologies has allowed the identification of some of the individual genetic variations that contribute to athletic performance. 

DNA tests offer the chance for individuals to discover their personal genetic advantages or barriers regarding performance in different sports.

Such tests do not only address to professional athletes but also to amateurs, who just wish to make the right choice of sport or enhance their performance in the sport they are already involved in. 

Despite the fact that our genetic makeup is something we carry for a lifetime and cannot be altered, it is possible to modify the effect of certain polymorphisms.

With the appropriate guidance even people who carry disadvantageous polymorphisms can improve their sport performance. 

Knowing your genetic needs, also makes it much easier to choose the appropriate diet and supplementation that will address to the personal needs for certain nutrients to perform better in a particular sport.

Genetics have a large influence over strength, muscle size and muscle fiber composition (fast or slow twitch), lung capacity, oxygen intake, flexibility, and endurance.

Your genes may also determine how your body responds to training, diet and other external factors.

About one in five people can train all they want but, because of their genetic makeup, are not likely to see much improvement in their endurance levels. 

My Gene Sport & Exercise Genetic Test analyses variations on 18 different genes that are associated with exercise performance.

 

Endurance and Power

As research into the connection between genes and sports continues, scientists have found a “power gene” which can set apart athletes successful in power sports (like football, weight-lifting and sprinting) from those who may not perform as well.

ACTN3 gene instructs your body to produce a special protein called alpha-actinin-3.

This is the protein which is found only in fast-twitch muscle fibres and is responsible for the explosive bursts of power necessary for successful sprinters or track cyclists.

Among elite power athletes the alpha-actinin-3 protein is nearly always present.

A variation of the ACTN3 gene has been identified that results in a deficiency in the production of the alpha-actinin-3 protein that has been associated with a natural predisposition towards endurance events.

Among elite endurance athletes – marathon runners and rowers – the variant form of the gene is more common.

 

The ACE gene

ACE (angiotensin-converting enzyme) is a well examined gene in relation to endurance capacity. 

It is part of a complicated cascade of molecules known as the renin-angiotensin system. 

ACE encodes an enzyme that converts Angiotensin I to Angiotensin II and is involved in the function of cardiovascular system and muscle performance.

The levels of the enzyme affect the regulation of blood pressure and are associated with the levels of lipids, glucose and total cholesterol in blood.

Angiotensin II affects vasoconstriction and regulation of salt and water balance through the release of aldosterone.

The variant of this gene is associated with vasodilation and enhanced blood flow to the working muscles and therefore increased endurance.

Individuals who carry the variant I, are shown to have increased rate of energy production during incremental exercise, which permits the muscles to perform better in activities with longer duration. 

ACE is also responsible for the degradation of the vasodilator bradykinin, regulation of inflammatory reactions to lung injuries, tissue oxygenation, erythropoiesis and skeletal muscle efficiency.

The variation on this gene gives the best of both worlds because it is associated with both endurance and power performance.

 

ADBR2 (β2 adrenergic receptor) 

ADBR2’s role in the functioning of the heart and lungs means that variation on this gene is associated with maximum oxygen consumption (VO2 max), therefore contributing to an increase in endurance performance.

The β2-adrenergic receptor (ADRB2) gene, in particular, is a candidate for variation in endurance performance levels because of its contribution to the regulation of energy expenditure and lipid mobilization from human fat tissue.

 

Muscle Performance

The CK-MM (creatine kinase isoenzyme MM) gene is responsible for the rapid regeneration of ATP during intensive muscle contraction.

The CK-MM gene is responsible for the rapid regeneration of energy during intensive muscle contraction and a rare natural human variant of CKMM is responsible for unusual increases in power. 

Under expression of this enzyme may therefore be responsible for muscular fatigue under normal circumstances.

 

AMPD1 (Adenosine monophosphate deaminase 1) is a highly active enzyme in the skeletal muscle that plays an important role in the muscle energy metabolism

Subjects with variation of this gene have diminished exercise capacity and cardiorespiratory responses to exercise.

 

PPARα (Peroxisome proliferator-activated receptor-α) is involved in the regulation of fat, glucose and energy metabolism. There is believed to be an association between the PPARα gene and muscle fibre type composition, depending on the individual genetic variation.

The variation on this gene is associated with higher proportion of fast type II muscle fibres and is well suited for power-based sports.

 

PPARγC1α (Peroxisome proliferator-activated receptor-γ coactivator-1α) produces a protein that regulates genes involved in energy metabolism.

This gene is involved in increasing the number of energy producing cells, called mitochondria, in the body. It is also associated with the proportion of slow type I muscle fibres.

Variation on this gene is associated with higher aerobic capacity, therefore endurance performance.

 

PPARGC1α’s role as a human endurance gene is suggested by numerous studies.

Studies have shown that exercise increases PPARGC1α mRNA levels and that overexpression of PPARGC1α leads to improved muscle resistance to fatigue. 

 

PPARγ (Peroxisme proliferator activated receptor-γ) gene is associated with regulating skeletal muscle glucose uptake and therefore the body’s glycaemic response to exercise.

As a result a variant on this gene is associated with muscle size.

 

PPARβ gene variation has been associated with increased muscle glucose uptake and a lower BMI in both athletes and non-athletes.

This genotype is associated with performance in long, middle and short distance endurance events.

 

HIF-1α (Hypoxia-inducible factor 1-α) is associated with affecting the oxygen and energy supplies in muscles and particularly muscles response to low oxygen levels.

This variant results in increased activation of other genes involved in energy metabolism and transport of oxygen to muscles.

Genetic studies have shown that a hyperactive form of this gene occurs twice as often among strength-trained athletes as in the normal population.

HIF-1α is ‘sensing’ the oxygen levels in cells, and the oxygen levels change by an order of magnitude in working muscle.

Variation on this gene is associated with a higher proportion of fast type II muscle fibres therefore, it is well suited to power-based events. 

 

VDR (Vitamin D Receptor) is the vitamin D receptor gene and is associated with muscle size and strength.

Variation on this gene is associated with moderately higher amount of muscle mass and therefore moderate higher level of muscle strength.

VDR expression decreases with age and VDR genotype is associated with fat-free mass and strength in elderly men and women. 

 

VEGF gene is involved in angiogenesis.

The cells of vascular system, in which blood flows, receive a signal to grow and multiply.

This is crucial before and after intensive exercise when blood flow needs to provide the muscle tissues with more oxygen.

This gene is associated with the oxygen supplies in muscles and affects the endurance capacity of individuals.

The insulin-like growth factor 2 protein (IGF-2), IL-6, TNF-α gene variations are associated with variable systemic CK response to strenuous exercise and help explain why some individuals are more susceptible to muscle damage when performing strenuous exercise that may not be accustomed to.

People with IGF2rs680 and INS-IGF-2 gene variation have been shown to have normal post-exercise levels of a substance called creatine kinase, which is a marker of muscle damage.

This genotype is also associated with normal post-exercise strength loss and normal levels of muscle soreness after exertion.

 

Tendons and Ligaments 

Ligaments and tendons fail to heal spontaneously and are a major clinical problem.

Polymorphisms within the COL5α1 (collagen type 5α1) gene have been associated with increased risk of musculoskeletal soft tissue injuries, in particular, Achilles tendon injuries.

Ligaments and tendons have a relatively similar structure, but different functions.

They have dense, collagenous structures with few cells and both can heal after injury, but the repaired tissue is weaker than normal and liable to re-rupture and adhesions is a common complication.

 

COL1α1gene variations are associated with normal (moderate) risk of cruciate ligament rupture and shoulder dislocation. 

Genetic testing will help identify individuals with advantageous physiology and a greater capacity to respond and adapt to training and a lesser chance of suffering from injuries.

 

Several gene polymorphisms might strongly predict the predisposition to becoming a top-class athlete, but an advantageous genotype not always translates into a champion, since a variety of psychological and environmental factors still influences gene expression.

Sport performances are also the result of hours spent in focused, prolonged, intensive training.

The early identification of young athlete's predisposition for a certain type of sport might be a vital component of many sport programmes and would also be useful to guide children towards the most suited athletic discipline. 

Genetic testing can help families decide in which sports individual kids are more likely to perform best and be successful.

The test can also help determine who may be prone to health problems, such as heart problems, for example, that can be exacerbated by athletics.

 

Further Reading:

 

References:

1. “Genetics and sport”, British Medical Bulletin, Oxford Medical Journals, 2009, http://bmb.oxfordjournals.org/content/93/1/27.full

2. Giuseppe Lippi†, Umile Giuseppe Longo‡, and Nicola Maffulli: Genetics and sports. Br Med Bull (2010); 93 (1): 27-47.

3. Molly S. Bray, James m. Hagberg, Louis Perusse, Tuomo Rankinen, Stephen M. Roth, Bernd Wolfarth, and Claude Bouchard: The Human Gene Map for Performance and Health-Related Fitness Phenotypes: The 2006–2007 Update. Med Sci Sports Exerc. 2009 Jan; 41(1):35-73. 

4. N.Yang, D. MacArthur, J. Gulbin, “ACTN3 Genotype Is Associated with Human Elite Athletic Performance”, Am J Hum Genet. 2003 September; 73(3): 627–631., Published online 2003 July 23., http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1180686/

5. Puthucheary Z, Skipworth JR, Rawal J, Loosemore M, Van Someren K, Montgomery HE, Genetic influences in sport and physical performance, Sports Med. 2011 Oct 1;41(10):845-59, http://www.ncbi.nlm.nih.gov/pubmed/21923202