Chinese scientists have successfully cloned two monkeys, an innovation that could mean huge progress in developing medicine to cure cancers and brain diseases such as Alzheimer’s, science WeMedia account The Intellectual reported Thursday.

Named “Zhongzhong” and “Huahua” — which together mean “China” — the two macaques are the first primates cloned through somatic cell nuclear transfer, the same technology that created Dolly the sheep in 1996.

The researchers, who are based at the Chinese Academy of Sciences’ Institute of Neuroscience, published their study in bioscience journal Cell on Wednesday.

Cloned animals allow scientists to better study diseases and the effects of drugs — and primates, being genetically similar to humans, make the best test subjects. In an interview with state news agency Xinhua, Sun Qiang, the lead contact for the paper, said that mass cloning of monkeys with the same genetic blueprint would become possible within the year. “This means that China will be the first to establish experimental animal models that can effectively simulate human diseases,” Sun said.

Scientists around the world have been experimenting with cloning other animals since Dolly, and have succeeded in cloning mammals including dogs, horses, and rabbits, according to the National Human Genome Research Institute, a U.S. government research body. Experiments involving primate cloning began in the early 2000s. In 2007, researchers in Oregon successfully cloned embryonic stem cells from macaques.

But the journey from embryo to live birth is a long one. Of the 149 monkey embryos produced in the study, 79 were transferred into surrogate mothers, and only two were born alive and healthy. Zhongzhong was born on Nov. 27, while Huahua was born around a week later, on Dec. 5.

“This is a technical milestone that has taken scientists from around the world 20 years to reach,” Emilie Marcus, chief editor of Cell, told Sixth Tone by email. She added that the publication process was faster than usual. “We always aim to disseminate groundbreaking science as quickly as possible, and in this case everything came together to provide a rapid and rigorous review process,” Marcus explained.

China is a dominant player in the field of animal cloning, and in commercializing such technologies. In July of last year, a research team in Beijing cloned the first gene-edited dog, and told Sixth Tone that they hoped to offer their service to the public.

Animal welfare advocates have voiced ethical concerns over cloning mammals, citing the risk of animal abuse and fears of unregulated human cloning in the future. However, Poo Muming, a co-author of the paper, said in an interview with state broadcaster China Central Television that though the breakthrough has removed obstacles for human cloning, the team has no intention to clone humans. According to The Intellectual, the research strictly followed international ethical standards for animal experiments.

This article has been updated to include comment from the chief editor of bioscience journal Cell.

Editor: Qian Jinghua.

(Header image: A handout distributed on Jan. 25 by the Chinese Academy of Sciences’ Institute of Neuroscience shows the two cloned macaques at a nonhuman primate research facility in Shanghai, Jan. 20, 2018. IC)