ABOVE: A transgenic Duroc pig designed to use food more efficiently and produce less environmental contamination in its waste
DR. XIANWEI ZHANG AND DR. ZHENFANG WU
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.
Normally, a sow will have a litter of 10 piglets from 15–20 fertilized eggs, says Jinzeng Yang of the University of Hawai‘i at Manoa. “When we do transgenic nuclear transfer, you need to do 200 eggs. You don’t know how many are alive, how many are dead. If you are lucky you get ...
