Researchers at the Chinese Academy of Sciences Institute of Neuroscience in Shanghai have used the old Dolly the Sheep technique to clone two identical female macaques, once again triggering a debate over the inevitability of human cloning in times to come.
After the success of Dolly back in 1976, scientists have cloned more than twenty mammal species, including dogs, cats, pigs and cattle, among others; but cloning primates had been an elusive proposition, until Zhong Zhong and Hua Hua happened eight and six weeks ago, respectively.
The Chinese team believes that this is the first step, and a big one at that, towards cloning a genetically identical population of monkeys, which would pave the way for scientists to study diseases in these primate populations, like never before, giving them a better shot at finding cures for diseases like cancer, Alzheimer’s and Parkinson’s.
Muming Poo, one of the authors of the research paper, said in a statement that the decision to clone primates was intended towards creating the perfect specimen for studying diseases and finding cures.
Poo is also the director at the Institute of Neuroscience at the Chinese Academy of Sciences Center for Excellence in Brain Science and Intelligence Technology.
While the improvised Dolly method has the potential to clone primates, humans included, the team had no plans of going that route, assured Poo.
“Humans are primates. So (for) the cloning of primate species, including humans, the technical barrier is now broken,” he said.
“The reason … we broke this barrier is to produce animal models that are useful for medicine, for human health. There is no intention to apply this method to humans.”
Arnold Kriegstein, director stem cell center at the University of California in San Francisco, said: “It’s a significant advance. Nobody has previously been able to create a cloned non-human primate.”
“You could create many cloned monkeys that all have the same genetic defect, then you would have a very powerful approach to study that disease,” he said.
Explaining why he was not surprised with the success of the Chinese, he said that elsewhere in the world, especially in Europe and the U.S., scientists have stopped researching on primates for ethical reasons.
“The trend in recent years has been to do less and less non-human primate research, largely because of the sensitivity surrounding using primates for research purposes. Many of the primate colonies in the United States have been closed down and the number of researchers working on non-human primates has dropped,” he said.
The researchers used a technique referred to as the somatic cell nuclear transfer or SCNT to produce Zhong Zhong and Hua Hua.
The procedure involves removing the nucleus of the monkey egg and replacing it with the nucleus from another body cell and stimulating the egg with an electric current to speed up the embryo development, before transplanting it into a surrogate monkey mother. The clone produced will be the exact replica of the donor animal.
During the course of their research, the scientists discovered that fetal cells produced far better results than adult macaque cells; Zhong Zhong and Hua Hua give credence to that.
“For many cell types, reprogramming is more difficult for adult cells than for fetal cells,” Robert Lanza, chief scientist at the Astellas Institute for Regenerative Medicine in Massachusetts, said. “That appears to be the case here as well.”
“It takes a lot of practice,” Poo said. “Not everybody can do the enucleation and cell fusion process quickly and precisely, and it is likely that the optimization of transfer procedure greatly helped us to achieve this success,” he added.
It was not all smooth sailing for the team, though. The two macaques were the result of almost 80 attempts, including six botched pregnancies and two clones that died soon after birth.
“We tried several different methods, but only one worked,” senior author Qiang Sun said in a statement. “There was much failure before we found a way to successfully clone a monkey.”
Both the monkeys, who are still being bottle-fed, are under observation and reported to be in good health, as is evident from the lab videos where they appear playful and active.
— Yicai Global 第一财经 (@yicaichina) January 25, 2018
— Ryan O’Hare (@thepragmaticape) January 25, 2018