I'm thinking about using this as a sort of meta explanation for how Orcs (and possibly other things as well) are different than humans (in muscularity), but I'm not entirely sure what the result of this would be.

What would be the expected appearance of a humanoid race with a suppressed myostatin gene? (Includes Men, Women, and Children)

  • (Bonus points for -accurate- picture examples, but explanations and approximations are perfectly valid as well.)

The Belgian Blue Cow is a notable example of such a mutation, and a helpful starting point for determining answers.


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    $\begingroup$ I asked a similar question a while back, with pretty much the same idea in mind. You might find it useful: worldbuilding.stackexchange.com/questions/10232/… $\endgroup$ – Philip Rowlands May 1 '17 at 15:41
  • $\begingroup$ This is a really cool idea as a way to create Orcs, etc. +1 $\endgroup$ – Paul TIKI May 1 '17 at 16:48
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    $\begingroup$ I add some info as comment because it does not answer the question. There is a very good reason for limiting muscle growth (myostatin) and the linked articles seems to be oversensational ("Wow, muscles"). Too many muscles increase both your basal metabolic rate and your necessary protein intake: In a famine such people die first. Tendons and bones can adjust themselves to higher load, but are prone to overstrain and cause permanent damage.Muscles need oxgen to work, so the whole cardiovascular system is under extreme stress. So for the story you could point out these weaknesses. $\endgroup$ – Thorsten S. May 2 '17 at 0:21

A deficiency in myostatin can and does occur in humans. Take, for example, a German boy who could lift 7-lb. weights with arms extended when he was 5 years old. You can find an image of him when he was a few months old in the article. Since his identity was not revealed, current images are likely hard to find. (Also, I don't want to be put on another watch list for trying to find them...)

Researchers have expressed health concerns in the boy's future due to his increased muscle mass. (Warning: paywall ahead) Research shows that a reduction in myostatin may also cause an increase in bone formation. Additionally, animal breeds with a myostatin deficiency have reproduction, dietary, and care issues relating to their increased muscle mass.

Humanoids with a myostatin deficiency would be bulkier through increased muscle and bone mass, but I would also anticipate them being fewer in number, due to all the special concerns that apply.

It's important to note that most breeds with a myostatin deficiency mutation have been engineered or selectively bred specifically for that trait, such as the Belgian Blue. This may be because nature cannot normally support such a creature due to the health concerns, especially as they apply towards reproduction.


From http://journals.plos.org/plosgenetics/articleid=10.1371/journal.pgen.0030079

enter image description here

This one is nice because you can see the difference between the +/+ wild type, the mh/+ heterozygote and the double mutant.

But my favorite picture of the myostatin mutant whippets is this one. enter image description here

because they both look like good dogs.

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    $\begingroup$ They're good dogs, Bront. $\endgroup$ – Skidsdev May 2 '17 at 8:20

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