Although several transgenic monkeys have been successfully generated using viral vectors, efforts to precisely target genes in primates have failed. Researchers in China have now achieved the feat by using Cas9 proteins directed by RNA molecules to specific sites in the genome, where the proteins generate mutations by introducing double-strand DNA breaks (Niu Y et al. Cell. doi:10.1016/j.cell.2014.01.027 [published online January 30, 2014]).
The investigators injected 1-cell stage embryos of cynomolgus monkey (Macaca fascicularis) with RNA molecules encoding Cas9, in addition to the so-called single-guide RNAs designed to target 3 specific genes. Eight of 15 embryos showed evidence of simultaneous mutations in 2 of the target genes.
Hampton T. New Method Allows for Precise Gene Targeting in Monkeys. JAMA. 2014;311(9):894. doi:10.1001/jama.2014.1396