- Genetic mutations can lead to super muscular people, animals and fish.
- Hyper-muscularity has, so far, been documented in humans, cattle, mice, sheep and dogs.
- Scientists are inducing the mutations in fish, with the hope that future research may cure certain muscle problems and even lead to larger fish for food.
Genetic mutations that cause mammals -- including humans -- to develop super ripped muscles, are now resulting in exceedingly buff fish, according to a paper in the latest issue of Animal Genetics.
The mutations can result in a doubling, or even tripling of muscle mass in affected species. So far, at least two children have been documented as having such changes to their genes. One is a young, and very beefy, German boy.
"At birth, the boy appeared to be extraordinarily muscular, with protruding muscles in his thighs and upper arms," lead author Anneleen Stinckens, paraphrasing a report by pediatric neurologist Markus Schuelke, told Discovery News. "Before he was five years old, he could hold 7-pound weights with arms extended, something many adults cannot do. He has muscles twice the size of other kids his age and half their body fat."
Yet another boy, Liam Hoekstra, was diagnosed with a clinically similar condition. Stinckens said that, based on reports, Hoekstra was able to do pull-ups, inverted sit-ups, Olympic-style iron crosses and more just months after birth. He has even punched "holes into walls during tantrums," according to accounts, and once accidentally gave his mother a black eye.
Stinckens and her colleagues studied data on the phenomenon in known affected species that, in addition to humans, include cattle, mice, sheep and dogs. She explained that a certain protein, called the myostatin (MSTN) protein, has a negative effect on muscle growth. Mutations related to this protein can cause it to completely fail, or to exist in very low levels.
"Since the MSTN gene can no longer exhibit its proper function or the levels of MSTN are very low, the negative control that was exercised by the MSTN protein disappears and muscles can grow much larger than they are supposed to," Stinckens explained.