Scientists in China have cloned five monkeys after editing genes to induce several human diseases like Alzheimer’s that they claim will help in medical research, an advance that is likely to raise fresh ethical concerns about gene editing. It is the first time multiple clones had been made from a gene-edited monkey for biomedical research, said Xinhua news agency.

The announcement follows the recent confirmation that the world’s first gene-edited human babies have been born in China, following an “unauthorised experiment” that has caused widespread disquiet in the scientific community.

Chinese scientists have cloned five monkeys from a gene-edited macaque with circadian rhythm disorders that are linked to sleep problems, depression and Alzheimer’s disease, the report said. The announcement was made in article published in National Science Review, a top Chinese journal in English.

The cloned monkeys were born in Shanghai at the Institute of Neuroscience of Chinese Academy of Sciences. Researchers said that the advance means that a population of customised gene-edited monkey models with uniform genetic background will be available for biomedical research. Previously, mice and flies were widely used for the research of such diseases, but these animal models differ greatly from human beings in terms of activity routines, brain structure and metabolic rate.

Disorders of circadian rhythm are associated with many human diseases, including sleep disorders, depression, diabetic mellitus, cancer and neurodegenerative diseases, such as Alzheimer’s disease.

The cloned monkeys, closer to human in physiology, make better models for research on disease pathogenesis and potential therapeutic treatments. In order to create an ideal donor monkey, researchers knocked out BMAL1, a core circadian regulatory transcription factor, using gene editing at the embryo stage. They selected one of the gene-edited monkeys with the most severe disease phenotypes as the donor. The fibroblasts of the donor were then used to clone five monkeys by somatic cell nuclear transfer, the same method used to generate Zhong Zhong and Hua Hua, the first cloned monkeys born in China at the end of 2017.

Different from Zhong Zhong and Hua Hua, generated by using fibroblasts from an aborted foetus, the new clones were made using a gene-edited young adult male monkey. “It shows that besides using foetus, batch cloning of gene-edited male monkeys with diseases is also feasible,” said Qiang Sun of the institute.

Sun said the research programme was reviewed and supervised by the institute’s ethic committee in accordance with international ethical standards of animal research. He said that the research signified the maturing of China’s somatic cell cloning.

Institute director Muming Poo said the research team would focus on cloning monkey models with different brain diseases in the future. Besides being used to study human brain diseases, the models will be used to test medicine effectiveness, which can help reduce the number of animal models used in experiments and lower the cost of medicine development, he said.

The announcement with photographs of the newly born monkeys comes in the backdrop of China punishing a scientist, He Jiankui, whose experiments resulted in the birth of twin gene edited babies. A special investigation team held that He defied the ban and carried out unauthorised experiments. He had announced their birth in November. The probe team said that while one volunteer delivered twins Lulu and Nana, another woman is pregnant.