Jianguo Zhao

These gene-edited pigs are hardy and lean—but how will they taste?

“Lean” may not be the term you associate with a good bacon strip or pork chop. But these leaner, cold-hardier piglets, created through CRISPR gene editing, could be a hit with the pork industry. The threat of hypothermia forces cold-climate farms to invest in heat lamps and other accommodations for their shivering piglets. And fatter pig breeds—though tasty—tend to grow more slowly and consume more feed than leaner ones to produce the same amount of meat. As an alternative to conventional breeding, researchers used the gene-editing technology CRISPR to introduce a gene called UCP1. Thought to have disappeared from the ancestors of modern pigs about 20 million years ago, the gene helps cells dissipate more heat and burn fat. Twelve transgenic piglets endowed with a mouse UCP1 gene were better able to maintain their body temperature than their unmodified counterparts when they were exposed to cold for a 4-hour period, the authors report today in the Proceedings of the National Academy of Sciences. And when the pigs were killed, fat made up less of their carcass weight—about 15% versus 20% in unmodified controls—while their average percentage of lean meat increased from about 50% to 53%. Will less fat make them less tasty? The authors don’t expect UCP1 to reduce the fat that accumulates in muscle fibers and contributes to flavor, but they’re now producing more pigs to make sure.