"The age of gene doping" - [The Role Of Genetics In Sport]

The world of sports has always been ruthless, especially during the time of the Cold War when scientists were intensively experimenting with pharmacology to improve the sports performance of athletes, without any regard to their health. Well, thanks to this, we currently know which substances and at what doses are harmful to human, what kind of adverse effects may cause their abuse, including in the long-term. Since then, an intriguing dependence was observed - all sportsmen will have different results, even while using the same performance-enhancing drugs, keeping the same diet, and completing the same training routine.

It is not a novelty to ascertain that sports performance strictly depends on genetic predispositions. Actually, it is the main factor determining whether an athlete will be capable of achieving notable sports results. But how to predict and recognize if somebody will be a successful sportsman in the future? Well, scientists and coaches moved a few miles forward, and their business correlated most closely in the sport's entire history. Thanks to genetic examination, it is possible to specify very precisely whether a young child has all of the necessary characteristics to become a great sportsman in the future or not. Also, by proper examinations (swab/muscle biopsy), it is possible to determine what disciplines a child should practice to achieve success in the future - disciplines based on strength, endurance, coordination, etc.

In the upcoming years, professional sports will change dramatically. Slowly, it is becoming possible to affect and modify the gene expression before a baby is born, and I bet it is already taking place, but well, who would let that fall into the public knowledge. The age of "genetic doping" has begun.

In this article, I will not describe all of the genetic processes in detail, as it is a subject for way more articles (even in the university class, the lessons have taken over 50 hours in total). Therefore, I will only write about the basics of the basics. However, if you wish me to write another extended article, describing more genes, let me know in the comments section.

The gene type depends on genetic heredity, environmental factors, and all possible mutations related to them. It is possible to specify their sequence in via DNA and RNA examination (DNA is composed of a chain of nucleotides: adenine, guanine, cytosine, thymine, deoxyribose, and phosphorus rest. DNA can be bound via transcription factor (TF), so a protein will also regulate the transcription process)

The following genes has the most tremendous influence on sports performance:

HIF-1a is a TF that regulates the expression of over 100 genes also the expression of enzymes in the glycolysis pathway (expression of GLUT1 / GLUT30, which induces the intensification of glycolysis. E.g., Pro582Ser of HIF-1a will improve glucose metabolism and increase the proportion of fast-twitch muscle fibers in vastus lateralis.

582Ser will be expressed in athletes who train in weightlifting.

Pro582 in athletes who train in endurance sports.

PPARs (peroxisome proliferator-activated receptors) regulate energetic metabolism. There are three isoforms: PPARA, PPARG, and PPARD. They determine beta-oxidation of fatty acids, which have a huge influence on, e.g., endurance, development of slow-twitch muscle fibers, ATP production, and the organism's response to training sessions.

AR gene - genetic predispositions also determine the quantity as well as the sensitivity of androgen receptors, which have a decisive influence on the response to androgens (read more about androgen receptors). In fact, the AR gene expression is the primary cause why men are better in sports than women.

ACTN3 - encodes the a-actinin-3 protein. Its expression promote the development of fast-twitch muscle fibers, minimize muscle damage induced by physical activity, and improve glucose metabolism in response to a training session.

Its genotype XX may worsen the development of fast-twitch muscle fibers but will improve endurance parameters instead.

Genotype XR and RR are associated with sprinter endurance.

MSTN - the gene that regulates myostatin production. Myostatin (growth and differentiation factor-8) is a protein secreted in skeletal muscles and bones that restrains the growth of muscles. Limited expression of the MSTN gene will lead to reduced myostatin production, thus firmly improving skeletal muscle hypertrophy potential and IGF-1 signaling, resulting in a high capacity for muscle & bone growth, recovery, and fat oxidation. The most common alterations in the MSTN gene makeup, which limits the regular gene expression, results from the mutation in the third exon of the myostatin gene (313 amino acid, cysteine -> tyrosine transition) and modification at nucleotide GIVS1+5 (guanine -> adenine). People with low expression of the MSTN gene are called to have the "Hercules gene" due to their huge potential for muscle growth and strength development, thanks to low myostatin activity.

AMPD1 - (deaminase AMP 1, isoform M) - the enzyme encoded by this gene, is a crucial factor that regulates the energetic metabolism of muscles during physical activity and is responsible for ATP production. Its T allele will worsen the function of AMPD, but the C allele will positively influence the anaerobic activity's effectiveness.

Several laboratories worldwide offer modifications of genes; however, regular bread consumers cannot modify their genes and improve personal physical abilities freely. It'll likely not change, at least until the end of this century.