Researchers at Nanjing Medical University and Yunnan Key Laboratory of Primate Biomedical Research in Kunming, China, have created genetically modified monkeys using a new method of DNA engineering known as Crispr. The infant macaques show that targeted genome editing is feasible in primates—a potential boon for scientists studying complex diseases, including neurological ones, and an advance that suggests that the method could one day work in humans. The work was reported in the journal Cell on Thursday.