Some very interesting scientific progress in China

China Breaks a Cloning Barrier: Primates. The development heralds the possibility of genetically engineered primates for drug testing, gene editing and brain research.

Researchers in China released this image of Zhong Zhong and Hua Hua, the first monkey clones made by somatic cell nuclear transfer. The two genetically identical macaques were born recently at the Chinese Academy of Sciences Institute of Neuroscience in Shanghai. PHOTO: QIANG SUN AND MU-MING POO / CHINESE ACADEMY OF SCIENCES

By Robert Lee Hotz Updated Jan. 24, 2018

In a world first, Chinese scientists say they cloned two monkeys by transplanting donor cells into eggs, a feat that could lead to genetically engineered primates for drug testing, gene editing and brain research.

The cloned macaque monkeys are the latest application of a test-tube technique called somatic cell nuclear transfer pioneered 20 years ago with the creation of the cloned sheep named Dolly. It has been used to clone 23 species from rodeo bulls to polo ponies and pet cats. But the ability to clone primates eluded scientists until the project made public Wednesday in the journal Cell.

“For the cloning of a primate species, including humans, the technical barrier is now broken,” said senior author Qiang Sun, director of the Nonhuman Primate Research Facility at the Chinese Academy of Sciences Institute of Neuroscience in Shanghai, in an interview. “In principle it could be used in humans, but there is no intention for us to apply this method to humans.”

The Chinese bioengineers made the two female monkeys by surgically replacing the nucleus of an egg with fetal donor tissue and then using special chemicals designed to trigger genes required for embryo development. The monkeys appear to be healthy and developing normally, the scientists said.

Two others, made at the same time using adult donor cells instead of fetal tissue, died within hours of birth, said the scientists, who couldn’t explain why. The failure is significant because adult cells are easier to obtain for cloning than cells from aborted monkey fetuses.

These microphotographs show the step-by-step process by which researchers in China created the first cloned monkeys. PHOTO: QIANG SUN AND MU-MING POO / CHINESE ACADEMY OF SCIENCES

The cloning project reflects China’s growing attention to primate research at a time when funding for primate studies has declined in Europe and the U.S. due to budget constraints, tighter regulations and growing reservations about the morality of animal research.

China sees primate research as the best way to find treatments or cures for a variety of brain diseases and disorders, and many Western scientists agree. But many Americans and Europeans think that using animals for medical research or drug testing is cruel.

China singled out the creation of primate disease models as a national goal in 2011. The number of businesses there breeding macaque monkeys—a mainstay of biomedical research—tripled between 2004 and 2013 to 34 from 10, according to data published in Nature.

“China has definitely taken the ball and run with it,” said primate reproductive biologist Catherine VandeVoort at the California National Primate Research Center, who wasn’t involved in the project.

Once they are available in larger numbers, cloned monkeys would be ideal as test subjects in many conventional medical studies because they are genetically identical. “You can treat one of them with a drug and leave the other one as a control. Then the only difference between them is the treatment,” Dr. VandeVoort said.

While technical hurdles remain, cloning also could become a way to speed up the breeding of primates given new traits through modern gene-editing techniques. Already, several research teams in China have altered monkeys by adding human genes, to make them better laboratory models than mice for probing brain-related disorders such as autism.

“Scientifically, there is an urgent need for nonhuman primate models of disease,” said reproductive biologist Keith Latham at Michigan State University, who uses gene-editing technology to alter rhesus monkey embryos. “The ability now to clone monkeys using this technique is a powerful tool in the toolbox.”

Write to Robert Lee Hotz at sciencejournal@wsj.com

Appeared in the January 25, 2018, print edition as 'China Clones Two Monkeys, Breaching a Genetic Barrier.'