Han Chunyu, a Chinese scientist who discovered breakthrough genome editing technology NgAgo, slammed accusations from foreign scientists who claimed it does not work, saying that he is willing to disclose his raw data.

Han, an associate professor at Hebei University of Science and Technology, discovered how to use the bacterial enzyme NgAgo to replicate and edit DNA and published his findings in the journal Nature Biotechnology on May 2. The discovery made a splash with scientists worldwide, who dubbed it a breakthrough in gene editing technology.

But many of these scientists have begun to question the technology's viability.

On Friday, Gaetan Burgio, head of the transgenesis lab at Australian National University, rescinded his previous statement that using NgAgo to edit gene fragments in mice is efficient.

"I have found strictly NO EVIDENCE for a genome editing with NgAgo after multiple attempts with various settings and 3 different genes," Burgio wrote on his Twitter account, adding that he believes conditions listed in Han's paper contradict the conditions needed for a successful replication.

Also on Friday, Lluis Montoliu, the former chairman of the International Society for Transgenic Technologies, wrote on Twitter, "After many similar negative results with NgAgo, Nature Biotech should ask original authors to share raw data and conditions."

David Stern, a group leader at the Janelia Research Campus, a neuroscience research center in the US, said on Twitter that "bottom line, NgAgo doesn't work as advertised."

"It's like they ganged up against NgAgo," Han told the Global Times on Sunday. He noted that researchers from MIT said they had reproduced his work and argued that claims that NgAgo is inefficient "seemed to have been written by outsiders."

Han said Nature Biotechnology has contacted him about the claims, and he said he is willing to share his raw data and conditions if the journal requires. "I will open my data under experts' supervision," Han said.

"Someone said they can repeat my work before, and less than a month later, they overturned their previous conclusion. This is actual science, not a joke," Han said.

According to the official website of the university, NgAgo is the first Chinese-made top-notch biotechnology, breaking the foreign monopoly on genome editing processes. The technology has extensive applications for agriculture and medicine, including in gene therapy for diseases like AIDS and hepatitis B.

In a Twitter post on July 2, following the start of controversy over Han's findings, anti-fraud campaigner Fang Zhouzi said there are many reasons why a new experiment result may not be replicable, including other scientists' failure to report successful replications, the obfuscation of critical steps in the process from the paper or the fabrication of the experiment's results by the originator. 

Fang also asserted that it is natural for people to have questions if their replication attempts do not work. The creator should dispel these questions rather than attacking or disparaging the questioners, which will only make people more suspicious, he advised.