Schwarzenegger Super Cows
There are two breeds of “Muscle Cows”, Belgian Blue and Piedmontese. Their incredible muscularity is not the result of steroids or any growth drugs. Both have a trait called “double muscling” which is characterized by an ultra-muscular physique and extreme leanness. What causes double muscling is a mutation that inhibits Myostatin, which is a protein that inhibits muscle development. The mutation also affects fat deposition causing the cattle to become ultra lean. Think of Myostatin as kind of a dam for muscle. It holds back muscle development like a dam holds back water. If Myostatin is blocked in someway, it stops holding back muscle growth and the body spills over with extreme muscular development. Myostatin inhibition causes muscle hyperplasia and hypertrophy. Hypertrophy involves enlargement in the existing muscle cells and hyperplasia is an increase in the number of muscle cells.
Cows are not the only animals to have a Myostatin mutation:
“The gene encoding myostatin was discovered in 1997 by geneticists Se-Jin Lee and Alexandra McPherron who produced a strain of mutant mice that lack the gene. These myostatin “knockout” mice have approximately twice as much muscle as normal mice. These mice were subsequently named “mighty mice”.
Naturally occurring deficiencies of myostatin have been identified in cattle by Ravi Kambadur, whippets, and humans; in each case the result is a dramatic increase in muscle mass. A mutation in the 3′ UTR of the myostatin gene in Texel sheep creates target sites for the microRNAs miR-1 and miR-206. This is likely to cause the muscular phenotype of this breed of sheep.” -Wikipedia
We know that certain cows, dogs, sheep, and even a few humans have naturally occurring myostatin deficiencies. We also know that scientists have created a strain of super muscular mice that lack the gene. Scientists are already working on inhibiting myostatin in humans for applications such as muscle wasting diseases like AIDS. Any time there is a discovery that can make a human leaner and more muscular it is a safe bet that athletes and bodybuilders will be interested in it.
More applications of gene doping are on the horizon and this type of body modification will likely be more controversial than steroids. The World Anti Doping Agency defines gene doping as: “The non-therapeutic use of cells, genes, genetic elements, or of the modulation of gene expression, having the capacity to improve athletic performance.”
Currently, it’s a little sketchy how anti-drug agencies will be able to test for gene doping. Once a genome is modified, unless the genome was mapped prior to that modification, how would you know there has been gene “doping”? There are obviously ethical, legal and social concerns regarding genetic manipulation in general as well as specifically for athletic purposes. One thing for certain is that once the technology exists, athletes will take advantage of it.