Sunday, 20 May 2012

Influence of Genetics on Sporting Performance

Student No. 42927518                                                                             

The recent advancements in genetics has enabled scientists to gain greater insight into the biological world around us – in particular, the correlation between phenotype and genotype in addition to patterns of inheritance and genetic mutations. Additionally, given the increasingly competitive nature of sport, it is not surprising that there has been an extensive amount of research conducted on particular genotypes that may be considered ‘favourable’ in the sporting arena. First discovered by William Hopkins in 1998, the angiotensin converting enzyme gene (also known as the ACE gene) provides the most comprehensive link between an individual’s genotype and athletic performance.

Figure 1.1 – Depicts the series of chemical reactions that
 occur as part of the renin-angiotensin system.
(Dekany et al. 2006)
The angiotensin-converting enzyme is part of the renin-angiotensin system (RAS). This system is involved in a complex series of chemical reactions (as illustrated by Figure 1.1) necessary to regulate water and salt homeostasis through the controlled release of the biological hormone aldosterone. However the function of ACE extends beyond that of the renin-angiotensin system to assist in the control of tissue oxygenation, respiratory drive and the regulation of skeletal muscle efficiency (Puthucheary et al. 2011). It is these physiological effects of ACE that have lead researchers such as Dekany et al. (2006) to conclude that there “seems to be a link between the (training) environment, the ACE gene polymorphism and the phenotype (athletic ability).” The two polymorphisms of the ACE gene are the insertion (I) and deletion (D) alleles. Consequently, during fertilization, and given that a person’s genotype consists of 2 alleles, an individual can inherit either two copies of the insertion allele (II) or the deletion allele (DD), or they can inherit one of each allele (ID). If a person possesses two copies of the same allele, they are said to be homozygous for that allele. Likewise, if a person has a copy of each allele, they are said to be heterozygous.

In 2009, Wackerhage et al. found that II carriers had the lowest concentration of ACE, while DD carriers had the highest concentration of the enzyme. Numerous researchers including Jones and colleagues (2002) have since concluded that the polymorphism of the gene results in physiological differences in specific tissues and systems that are advantageous to specific athletic disciplines. The D allele for example has been found to appear at a higher frequency amongst those individuals competing at the elite level in strength-based athletic events, such as swimming 50 metres freestyle. This has been linked to the presence of the D allele corresponding to greater exercise-induced strength increases when compared to those individuals lacking this allele. Similarly, the I allele has been linked to ‘elite’ athletes who participate in endurance-based athletic events such as marathons and mountain climbing. It has been suggested that this is a result of the I allele favourably altering metabolic pathways for endurance athletic events.

Recent advancements in genetics and gene technology have lead to a significant increase in the current state of knowledge in this field. The impact of genetics on athletic ability does however remain in its infancy with further study and research still required.

References
Dekany, M, Harbula, I, Berkes, I, Gyore, I, Falus, A & Pucsok, J 2006, 'The Role of Insertion Allele of Angiotensin Converting Enzyme Gene in Higher Endurance Efficiency and Some Aspects of Pathophysiological and Drug Effects', Current Medical Chemistry, vol 13, no. 18, pp. 2119-2126.

Hopkins, WG 1998, ‘Performance Gene Discovered’, Sportscience, vol. 2, no. 4, pp. 475-482.

Jones, A, Montgomery, HE & Woods, DR 2002, 'Human Performance: A Role of the ACE Genotype?', Exercise and Sport Sciences Reviews, vol 30, no. 4, pp. 184-190.

Puthucheary, Z, Skipworth, JR, Rawal, J, Loosemore, M, Van Someren, K & Montgomery, HE 2011, 'The ACE Gene and Human Performance', Sports Medicine, vol 41, no. 6, pp. 433-448.

Wackerhage, H, Miah, A, Harris, R, Montgomery, H & Williams, A 2009, 'Genetic Research and Tesing in Sport and Exercise Science: A Review of the Issues', Journal of Sports Sciences, vol 27, no. 11, pp. 1109-1116.


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