Han Chunyu, a Chinese scientist, published his DNA-guided genome editing technique, NgAgo, in the magazine Nature Biotechnology on May 2. However, since his results have not yet been replicated, Han is now encountering doubts and questions from his peers.

On July 29, a blog post pushed the story to new levels of publicity. Gaétan Burgio, group leader and head of the transgenesis facility at the John Curtin School of Medical Research (JCSMR) within ANU College of Medicine, Biology and Environment, published the results of his own experiment, which used mice to try to reproduce Han’s results. On his blog, Burgio wrote that he holds “serious doubt [about] NgAgo over its endonuclease activity.” Meanwhile, he urged "Nature Biotechnology" to petition Han to release his raw data and experimental conditions to the public.

On the afternoon of July 30, Lluis Montoliu, former chairman of the International Society of Transgenic Technology (ISTT), replied to an email from a Caixin reporter. In his email, Montoliu explained that every experiment trying to reproduce Han’s results since Han's paper was published has so far failed.

Facing mounting doubts, Han replied that his results can only be proven through science, and he will not respond to media speculation, which in his opinion is “not scientific.”

Other Chinese scientists have remarked that doubts and second-guessing are very common in science. Qiu Zilong, a researcher with the Institute of Neuroscience under the Chinese Academy of Sciences, wrote in an online Q&A that, “we have enough time to optimize our technology [to test Han’s paper] since the paper was published only two months ago. As for the authenticity of Han’s paper, it’s up to a third-party organization to decide.”

Typically, journals will launch an investigation into papers that are met with great skepticism. If the doubts are confirmed in this case, the journal will either make corrections or delete the paper. At the time of writing, no comments had been made by Nature Biotechnology.