Question

How might variants affect athletic ability?

Answer 1

Genetic factors contribute majorly in athletic ability. More than 20 genetic variants have been associated with physical performance and athletic ability. Each sport has unique characteristics, with each requiring athletes with different body morphology. Genetic factors are estimated by heredity of a trait. Height, body type are some of the heritable factors. Some genes that determine athletic ability are:

1. ACE gene encodes for angiotensin-1 converting enzyme, a part of the renin-angiotensin system that controls blood pressure. The ACE I allele is a 287 bp insertion associated with lower serum and tissue ACE activity. The D allele has the 287 deletion that leads to higher serum and tissue ACE activity. The ACE I/I genotype is associated with endurance performance and higher exercise efficiency. The D/D genotype is associated with strength and power performance. Both these alleles exhibit differences in ethnicity.

2. The ACTN3 gene encodes for the protein α-actinin-3 that is expressed in the fast type II muscle fibers during intense exercise. A premature stop codon (X) replacing an arginine (R) at position 577 causes an R to X polymorphism. The RR allele RR genotype increases sprinting ability and muscle strength. Hence, people with these alleles are better in football, weight-lifting or sprinting. The XX genotype reduces sprinting ability and muscle strength. People with this genotype perform better in cross-country skiing, distance running or swimming

3. Collagen is the primary structural component of tendons and ligaments. Variants in genes encoding collagen (COL1A1 and COL5A1; MMP3 responsible for repair and wound healing of connective tissues, and TNC that encodes an extracellular matrix protein, are linked increased risk for tendinopathy. Presence of multiple alleles increases risk of injury in athletes. C

4. Mutation in erythropoietin receptor allows athletes to make red blood cells with higher capacity to carry oxygen. EPOR signals the increased production of RBCs.

Genetic testing will allow athletes to understand their physiology and to choose the right sport. Twins are excellent system to study effect of genes on athletic inheritance. Identical twins have similar athletic abilities while fraternal twins don’t.