How do genetics help power your muscles?
The Weekly Gene: AMPD1
Exercising requires energy, which (as we all know) can sometimes be hard to come by. Working out requires more than just feeling awake and energized, though—our muscles actually need molecules that are high in energy in order to function. Coded within the human genome are specific genes which are dedicated to the regulation and storage of energy. These genes help muscles maintain a balance between energy production and energy use, but variants in some genes can disrupt this balance. One such gene is called AMPD1.
The first law of thermodynamics states that energy can neither be created nor destroyed. Accordingly, our body doesn’t create energy, but it does manipulate it. The human body stores energy in the form of adenosine triphosphate (ATP). ATP is a molecule that’s packed with energy, mostly taken from sugars we’ve consumed. This bundle of energy can be used by proteins in our body to carry out many different functions. In muscles, proteins responsible for the contraction of the muscle fiber use ATP to help them generate the power needed to perform a task (such as lifting a weight or propelling the body forward when running)1. In other words, ATP is critical to the muscle function and is required in high levels to meet the demands of exercise, which is where AMPD1 comes in1.
AMPD1 was one of the first genes associated with human athleticism and has since been studied in elite athletes ranging from Ironman competitors to top level wrestlers2,3. This gene is predominantly used in skeletal muscle where it helps muscle maintain the ability to make and use ATP. It does this by eliminating a byproduct of ATP known as AMP (or adenosine monophosphate)1-3. Removing this byproduct is similar to unclogging a drain—failure to do so can cause a buildup of AMP and prevent the body from making more ATP1.
A specific version of the AMPD1 gene has been associated with a decreased ability to remove AMP in muscle cells1-3. This is because a change in the DNA coding for AMPD1 prevents the gene from working correctly, resulting in a failure to produce the AMPD1 protein. Genetic studies have shown that people who lack AMPD1 may experience muscle cramping, decreased muscle power, and a faster rate of fatigue during exercise2,3. Further studies have shown that elite athletes are less likely to have inherited this gene variant2,3. These results should not discourage anyone who has inherited it, though, because studies have also shown that this variant does not always have an effect—some people with it perform as well in sports as those without it3.
It’s important to remember that athleticism is the result of many different factors including a person’s environment, access to resources, diet, and partly their genetics. Research into how these factors interact (and how AMPD1 might contribute to a person’s athleticism) are ongoing. Ultimately, DNA tests like MyTraits Sport by Intelliseq analyze your DNA and provide you with insights about your AMPD1 gene. With these tests, you can see how multiple genes in your body may influence athleticism and maybe even learn how to leverage this information when trying new workout routines.
2Grealy, Rebecca et al. “Evaluation of a 7-Gene Genetic Profile for Athletic Endurance Phenotype in Ironman Championship Triathletes.” Ed. Klaus Roemer. PLoS ONE 10.12 (2015): e0145171. PMC. Web. 19 Dec. 2017.
3Ahmetov, Ildus I., and Olga N. Fedotovskaya. “Current Progress in Sports Genomics.” Advances in Clinical Chemistry, 11 Apr. 2015, pp. 247–314., doi:10.1016/bs.acc.2015.03.003. Web. 19 Dec. 2017