Actinin-3 Essay

1395 Words 6 Pages
Alpha-actinin-3 is a protein that is encoded by the “athletic gene”, ACTN3, in humans. ACTN3 is located at the long arm of chromosome 11 and encodes for the expression of alpha-actinin-3 protein in fast glycolytic muscle fibers. Fast glycolytic fibers, or type IIb, are responsible for the generation of rapid forceful contractions. There are some individuals who do not have a working version of this gene, which causes the muscle protein to not be created. These individuals are said to have the ACTN3 mutation and do not respond well to speed or strength activities. There are three possible genotypes for the ACTN3 gene, which include: RR, RX, and XX. Homozygous XX individuals lack the expression of ACTN3, while R carriers have …show more content…
This mutation is seen in 18% of healthy white individuals, due to a common stop codon in the polymorphism in the ACTN3 gene. An evolutionary “trade-off” exists in the performance traits for endurance and speed. Africans have the lowest incidence of the ACTN3 mutation while Asians have the highest. This could be because of how much energy was needed for these individuals in different parts of the world. It was interesting to see the allele frequency for this gene in elite athletes and how it was expressed based on the sport or level of complexity that the athletes performed at. It was striking to see that the genotype frequency displayed from this study showed that power Olympians were absent of the XX genotype completely, while the endurance Olympians had it. Power athletes do need to have the ability to endure an exercise, such as lifting, but not for a long period of time. Overall, the RX genotype had a much higher frequency in power athletes, probably because they need the ability to endure the weight and have the strength and power to carry at such a high intensity. What I found to be really thought-provoking was that all the males tested in this study carried at least one form of the R allele. As stated in the previous paragraph, the R allele carriers have an advantage in power, speed, and strength activities. This connects to the information I have learned from my strength …show more content…
The article mentioned additional variants linked with elite power and sprint performance, but eventually concluded that Alpha-Actinin-3 was the only gene that showed a genotype and performance association with elite power athletes. This association was supported by an ACTN3 knockout mouse model. This knockout mouse model showed that the mice with the XX genotype had reduced muscle mass due to the decreased diameter of fast muscle fibers, decreased grip strength, and increased endurance capabilities. The phenotypes of the ACTN3 knockout mice served as a great model in association humans to this gene and how they perform with an XX

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