Cloned by researchers from the Institute of Neuroscience of Chinese Academy of Sciences in Shanghai, the two monkeys represent the first time that humans have been able to make primate clones using the same technique that created Dolly the sheep.

While in the past we’ve been able to clone rats, pigs cats and dogs, primates have proven to be particularly difficult to clone.

In addition to being a technical achievement, senior author SUN Qiang, Director of the Nonhuman Primate Research Facility at the Academy believes that it represents a far more important shift in how we tackle some of the world’s most serious diseases.

“You can produce cloned monkeys with the same genetic background except the gene you manipulated. This will generate real models not just for genetically based brain diseases, but also cancer, immune or metabolic disorders, and allow us to test the efficacy of the drugs for these conditions before clinical use.” explains SUN.

These two are not the first primates to be cloned, that honour goes to Tetra, a rhesus monkey made in 1999 using a different form of cloning known as embryo splitting.

Embryo splitting, although effective, can only produce 4 offspring at any one time, limiting its usefulness in a laboratory environment.

Zhong Zhong and Hua Hua were instead created using a technique known as somatic cell nuclear transfer where you remove the nucleus from an egg cell and replace it with another nucleus from differentiated body cells. This reconstructed egg then develops into a clone of whatever donated the replacement nucleus.