The Superpowers of Genetically Modified Pigs

Several years ago, at a lab near a massive experimental farm in Guangdong Province in China, scientists prepped a whopping 4,008 genetically modified pig embryos for implantation into just 16 sows. It's a numbers game these livestock engineers are familiar with; knowing that many embryos will not survive the procedure--and those that do may not make it through gestation or life beyond the womb--the researchers overproduce embryos and hope for the best. For this project, Jinzeng Yang's colleagues were trying something scientifically ambitious: introducing genes for three microbial enzymes into the pigs' genomes that were intended to help the animals metabolize their feed more efficiently, while producing less nitrogen and phosphorus waste.