Gene therapy is most commonly used in the medical world; however it can be used to enhance the performance of the athlete.
According to the World Anti-Doping Agency (WADA), gene doping is defined as the non-therapeutic use of genes, genetic elements and cells that have the capacity to enhance athletic performance.
Gene doping is essentially the improper use of gene therapy. Instead of injecting DNA into a person's body for the purpose of restoring some function related to a damaged or missing gene, gene doping involves inserting DNA for the purpose of enhancing athletic performance. The required gene and a transgene is cloned into a gene expression construct and delivered to the appropriate tissue by a suitable vector.
There are endless possibilities for gene doping to be used as a performance enhancement which makes it a challenge to detect.
Gene doping has been banned as a means of performance enhancement by WADA since 2003, however it is incredibly difficult to detect.
Researchers at the National Measurement Institute in Sydney developed a gene doping test to detect synthetic versions of the EPO (Erythropoietin) gene which was first used to correct anaemia in 1987. EPO is a peptide hormone that is produced naturally by the human body. EPO is released from the kidneys and acts on the bone marrow to stimulate red blood cell production. Thus increasing the bodies ability to deliver a higher volume of oxygen to muscle cells.
The test identifies differences between endogenous and synthetic versions of the EPO gene. In the human genome the EPO gene contains four introns which are removed after the gene is transcribed. As gene doping relies on reverse transcription, the synthetic version of the EPO gene would therefore not contain the intronic sequences. Therefore, this test can be used to identify if a performer is using gene doping to enhance their performance. This test was used recently in the 2016 Rio Olympics.
Another method of gene doping is where the gene therapy is applied directly into muscle tissue. An athlete can be injected with a vector which is capable of producing insulin growth factor which has been shown in a study to generate huge muscles in mice. This would be extremely difficult to test as it is only detectable through a muscle biopsy as it is undetectable through blood and urine tests.
Unfortunately, as scientists make further advances in gene doping it will become more common practise in the sports world. It’s extremely likely that gene doping will become a larger issue in future Olympic Games, including the next games in Tokyo. As current tests for gene doping are ineffective and there are many possibilities of gene doping many argue that sport should embrace gene doping as authorities will find it difficult to eliminate it. Yet, many argue against this due to the health risks associated with gene doping.
Once again, as we progress and enhance our therapeutic medicine, sport science can use these tools to give coaches and their athletes the edge, to help trick the systems and to get ahead of the field. I do not know what the solution is in breaking this cycle, especially when there is so much at stake: fame, fortune and notoriety. The people who practice ‘Cheating’ methods will always be one step ahead of the governing bodies and anti-drug administrators.
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MIAH, A., 2006. Rethinking Enhancement in Sport. Annals of the New York Academy of Sciences, 1093(1), pp.301-320.