Chinese scientists have been able to clone two macaques using the same technique that was responsible for Dolly — the world's first cloned mammal. This is the first time that a primate has been ever been cloned.

This new development brings researchers one step closer to human cloning.

Nuclear Transfer

The method used to produce the cloned sheep Dolly is known as a somatic cell nuclear transfer. When scientists used this method they were able to make viable embryos but they would fail to mature into healthy animals.

SCNT is done by taking the nucleus of a cell from tissue, then swapping it into a fertilized egg that has had its own chromosomes removed. The embryo is then treated with enzymes which return it to an early embryonic state like a just-fertilized egg. This technique can create infinite clones from the same donor.

Chinese scientists had to use the new technique because of previous cloning failures. Techniques used include a new type of microscopy to have a better view of the cells during the handling and using compounds to encourage cell reprogramming. The second technique hadn't been tried on primates before.

Even after the new techniques, the scientists had a low success rate. 79 embryos produced six pregnancies, out of those pregnancies only two were born. Cells that were reprogrammed came from fetal monkeys, not adult monkeys.

The monkeys were named Zhong Zhong and Hua Hua.

This is the first time that scientists have been able to clone primates through SCNT. This advance would make it easier to use and reproduce in large numbers.

Research Applications

Using this technique scientists would be able to create a large number of genetically identical monkeys that could be used for research into human diseases. Research into Alzheimer's and Parkinson's disease are two conditions that scientists would look at first. Scientists will be interested to use identical populations to conduct more research into genetic diseases.

"If you have a population of nonhuman primates that are genetically identical, that's a really, really powerful model to study human disease, underlying mechanisms, and potential cures," said Kevin Sinclair, a biologist at the University of Nottingham. "But it has to be done on a case-by-case basis to justify doing that."

The U.S. has more strict guidelines when it comes to genetic research on primates, this research is more accepted in China. Researching using primates has been on the decline in the U.S. In 2013, the U.S. announced that it would be retiring most of their 360 research chimpanzees.