Helen Shen in Nature:
The ultimate potential of precision gene-editing techniques is beginning to be realised. Today, researchers in China report the first monkeys engineered with targeted mutations1, an achievement that could be a stepping stone to making more realistic research models of human diseases. Xingxu Huang, a geneticist at the Model Animal Research Center of Nanjing University in China, and his colleagues successfully engineered twin cynomolgus monkeys (Macaca fascicularis) with two targeted mutations using the CRISPR/Cas9 system — a technology that has taken the field of genetic engineering by storm in the past year. Researchers have leveraged the technique to disrupt genes in mice and rats2, 3, but until now none had succeeded in primates.
Previous attempts to genetically modify primates have relied on viral methods4, 5, which create mutations efficiently, but at unpredictable locations and in uncontrolled numbers. Prospects for primates brightened with the emergence of the CRISPR/Cas9 gene-editing system, which uses customizable snippets of RNA to guide the DNA-cutting enzyme Cas9 to the desired mutation site. Huang and his team first tested the technology in a monkey cell line, disrupting each of three genes with 10–25% success. Encouraged, the scientists subsequently targeted the three genes simultaneously in more than 180 single-celled monkey embryos. Ten pregnancies resulted from 83 embryos that were implanted, one of which led to the birth of a pair with mutations in two genes: Ppar-γ, which helps to regulate metabolism, and Rag1, which is involved in healthy immune function.
More here. (Note: CRISPR is one of three most important biologic discoveries of the last century.)