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Know Your Genes: ACTN3- “The Speed Gene”

Muscle power
Endurance
Fast Twitch fibers
Type II fibers

The skeletal muscle consists of two types of fibres – fast twitch and slow twitch. The slow twitch fibres work efficiently for a long period of time while the fast twitch fibres are responsible for short and sudden burst of power necessary for sprinting or weight lifting. The ACTN3 gene is associated with the synthesis of alpha actinin 3 protein present in the fast twitch fibers (Type II) of skeletal muscle. The alpha actinin 3 protein is found almost exclusively in the fast twitch fibres.
Specific alleles of this gene are known to either increase or decrease the extent of muscle power based on the synthesis of the alpha actinin 3 protein. People with the C variant of the gene are associated with higher muscle power due to the presence of active alpha actinin 3 protein while people with the T variant of the gene are associated with lower muscle power due to the presence of inactive alpha actinin 3 protein. As a result, sprint or power athletes tend to have at least one copy of the C allele. Both the C and the T allele carriers have selective advantages in different environmental conditions.

GenotypePhenotype
TT
  • [Limitation] Absence of active form of alpha actinin 3 protein
  • [Limitation] More likely to have lower muscle power
  • [Advantage] Better suited for endurance based activities
CT
  • [Advantage] Presence of active form of alpha actinin 3 protein
  • [Advantage] More likely to have moderate muscle power
CC
  • [Advantage] Presence of active form of alpha actinin 3 protein
  • [Advantage] More likely to have higher muscle power
  • [Advantage] Better suited for sprinting and power activities

How can this information be used?

It is important to choose appropriate exercises based on the genetic profile.

For people with C variant (High Muscle Power)

  • Greater power due to presence of the active alpha actinin 3 protein allows you to perform a variety of power based activities like sprinting and weightlifting
  • High intensity workout will yield better results
  • Most elite sprinters and power athletes have at least one copy of this gene

For people with T variant (Low Muscle Power)

  • Lower muscle power due to absence of the active alpha actinin 3 protein
  • Slow and efficient muscle performance will aid in endurance activities like long distance running, playing tennis, basketball and dancing.
  • Low to mid intensity workouts for longer durations will yield better results

References:

  1. Nan Yang, Daniel G. MacArthur, Jason P. Gulbin, Allan G. Hahn, Alan H. Beggs, Simon Easteal,and Kathryn North; “ACTN3 Genotype Is Associated with Human Elite Athletic Performance”; Am J Hum Genet. 2003
  2. Seok-Ki Min, Seung-Taek Lim, and Chang-Sun Kim; “Association of ACTN3 polymorphisms with BMD, and physical fitness of elderly women”; J Phys Ther Sci. 2016 Oct
  3. http://kohlmanngen677s13.weebly.com/
  4. http://playdna.co.uk/images/Sports%20Brochure%20example%20pages.pdf
  5. https://blog.athletigen.com/actn3-the-sprint-gene-and-selection-for-non-functional-protein/
  6. https://www.dnafit.com/blog/gene_in_focus_-_part_3:_actn3_3307.asp
Find out which variation of the gene you carry and more at www.xcode.in

Nutrigenetics, fitness genetics, health genetics are all nascent but rapidly growing areas within human genetics. The information provided herein is based on preliminary scientific studies and it is to be read and understood in that context.

Amrita Surendranath
Amrita Surendranath
Amrita has a Masters in Human Genetics which fuelled her passion for genes and their diktats. She loves converting genetic research into exciting scientific news with a punch. 10 years on, her interesting insights have covered a range of topics that include cancer, diabetes, nutrition, fitness and more. A pulse on what’s interesting aids in decoding laboratory data into useful science that could empower people into molding healthier lifestyles.