Though it may sound like a David Chang
fantasy, the idea of pigs bursting with meat and yes, extra ham and thicker chops is nothing to snort at. Assuming, of course, that such genetically modified pork will eventually find its way into the supermarket – a very real possibility.
In late June, biologists in South Korea increased the likelihood of this reality, with the introduction of pigs with super-muscled backsides, as detailed in Nature
. The researchers used gene editing – less disruptive than genetic modification since it does not introduce new genetic material from another organism – to block a single gene that normally keeps muscle mass and at normal levels and helps regulate fat deposits. The gene, myostatin (MSTN
), is sometimes disabled naturally in humans and dogs, and most notably in the Belgian Blue
breed of cattle, resulting in leaner, double-muscled pigs.
In the case of Belgian Blue cattle, the disruption of MSTN
occurred through selective breeding and was first documented in 1808, suggesting that similar, double-muscled pigs could also be arrived at through conventional breeding techniques. Gene-editing speeds up this process and is one of the reasons many are advocating for broader acceptance of these pigs, and other animal products resulting from minimal gene-editing techniques. Other varieties of gene-edited pigs exist, such one revealed
earlier this year that has one letter of their genetic coded flipped in order to make their immune system more similar to that of the African swine disease-resistant warthog. Such work follows on years of study into the genomics of common swine diseases that cost Canadian producers as much as $100 million
per year and sits alongside current efforts to reduce disease and better manage the nutritional content of pig feed
to produce healthier animals.
But, having these pigs in research facilities doesn’t put them on the plate. To date, no GM or gene-edited animal has received Health Canada approval, but the arguments in favour are building, such as reductions in cost, antibiotic and environmental impact, as well as improved precision in gene-editing technologies. And the animals themselves aren’t quite ready for mass production -- in the case of the super-muscly pig, only 13 of the first 32 survived to eight months, and only two were still alive at the time the Nature article was published. Pigs with extraordinarily large hindquarters also have difficulties giving birth, a trait they share with the Belgian Blues, where caesarian sections are routinely scheduled to ensure live birth of offspring. Such medical intervention is costly and carries additional risks for the animal.
Despite these challenges, the research team is pushing forward and says the pigs were not intended to be bred for meat production. Rather, their aim is to cultivate sperm from the animals that would then be sold into existing pork farms – their sights are currently set on China, where a more favourable regulatory environment exists -- there to be inseminated into regular pigs. The offspring of the two pigs, one with the knocked-out MSTN
gene, is hoped will be healthier than the double-muscled variety, albeit with less bulk.
Personally, I hope they call the new hybrid the “Extra Large Pork Bun.” I’m pretty sure David Chang would approve.