The Rs1815739 Mutation
A mutation (rs1815739; R577X) has been identified in the ACTN3 gene which results in a deficiency of alpha-actinin 3 in a significant proportion of the population. Based on ethnicity the deficiency is found in 20-50% of people. Generally, Africans have the lowest incidence of the mutation whilst Asians have the highest. Scientists believe that variations in this gene evolved to accommodate the energy expenditure requirements of people in various parts of the world.
Studies have linked the fiber twitch type with ACTN3, i.e. fast twitch fiber abundant individuals carry the non-mutant gene version. Also, studies in elite athletes have shown that the ACTN3 gene may influence athletic performance. Whilst the non-mutant version of the gene is associated with sprint performance, the mutant version is associated with endurance.
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