Sha teamed up with Xingxu Huang of Nanjing University and Weizhi Ji of the Yunnan Key Laboratory of Primate Biomedical Research and Kunming Biomed International. The researchers injected messenger RNA molecules encoding Cas9, in addition to single-guide RNAs designed to target three specific genes, into one-cell-stage embryos of cynomolgus monkeys. After sequencing genomic DNA from 15 embryos, they found that eight of these embryos showed evidence of simultaneous mutations in two of the target genes.