In order to breed animals that produce far superior quality meat, breeders typically spend decades making selective crosses between methodically chosen animals. A team of scientists with Chinese and South Korean members is developing a method to dramatically shorten this process.

By editing a specific gene from DNA extracted from common pigs, they were able to breed animals that develop an advantageous musculature in a short time, which ensures less fat between fibers and more meat per animal. It is the same result obtained by the breeders mentioned above, but with an extremely reduced cost and time compared.

The scientists used a genetic engineering technique called TALEN - the Transcription of Target Gene Activator-Like Effector Nucleases - that uses “programmed” enzymes to look for and cut specific DNA sequences, ignoring any other genetic material. In this case, the sequence deleted was that of the myostatin gene, which inhibits muscle growth while an embryo is developing, preventing it from becoming too large.

The pigs in the image have overdeveloped muscle, thanks to the elimination of the myostatin gene - Image: Nature

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With the elimination of this gene from DNA, muscle cells do not hinder their development, which causes them to develop faster and more sharply. The genetic code tries to repair the damage done, but ends up with that damaged sequence, which makes muscle cells dysfunctional, that is, that they don't behave the way they should.

The altered DNA was then introduced into porcine fetal cells and 32 piglets were cloned from this initial sample. However, only 13 of them were over eight months old because of their large size. Currently, only two of the pigs are still alive, but only one is considered healthy.

The research has not yet been published, but the goal of the long-term study is to develop the first genetically altered animals that are approved for human consumption. Because the technique alters one gene from the animal itself, rather than adding genes from another, a method most commonly used in genetic engineering, they believe regulatory approval would be easier to obtain.

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Concern for consumer health and environmental change are reasons why government agencies such as the US Food and Drug Administration (FDA) and the like have not yet allowed genetically modified animals to be consumed by humans.

Instead of continuing to alter pigs' DNA to prevent animals from dying due to disproportionate growth, the research team has a different idea. Their goal is to seek approval from China's regulator, considered less rigid than the others, and to sell genetically altered swine sperm to Chinese farmers.

Crossing the modified sperm with eggs from normal animals would cause only part of the DNA to be altered, which should generate only partially developed musculature in pigs. However, this would still result in pigs that would produce more meat and with less fat in their fiber.

Consequently, bacon extracted from these animals would be "leaner". You just can't know if it would be as tasty as the original.