© Hervé VanderschurenA research project that used CRISPR technology to make cassava resistant to mosaic virus instead allowed the virus to mutate and be passed down to the next generation. This photo compares diseased cassava, left, with healthy plants.
A team of biologists is warning other researchers to be careful when using CRISPR gene editing, after finding the technology could backfire.

According to a newly released scientific paper, the biologists used CRISPR on the cassava plant, hoping the technology would make it resistant to the mosaic virus.

However, the method, which lets researchers precisely delete genes in a plant's DNA, didn't make cassava resistant, instead causing viruses to mutate and be passed down to the next generation.

Devang Mehta, who was part of the cassava study and is a postdoctoral fellow with the biological sciences department at the University of Alberta, said he believes the mutated virus propagated because it was genetically selected.

He said that when they used CRISPR to delete a gene, the technology also caused viruses to evolve.

"When you cut with CRISPR and the DNA repairs itself, there are usually mistakes that happen. When it repairs itself, it produces different mutations each time," Mehta said.

"We think when the virus got cut, each individual virus wanted to repair itself and produce different mutations"

As well, one virus mutation likely meant the biologists wouldn't be able to use CRISPR interventions on the propagated plants, he added.

"Because this one mutation seemed to give it resistance to CRISPR, it would get selected for evolutionary species."

Mehta worked on the project in Switzerland with the help of biologists from the University of Liege in Belgium and the Swiss Federal Institute of Technology.

In a controlled greenhouse setting, the team spent eight weeks trying to make cassava resistant to the virus.

When infected, Mehta said, the cassava plant is unable to develop roots. The roots are commonly consumed in South America, Africa and Asia.

Mehta said the CRISPR method wouldn't pose the same risks for other agriculture products, noting canola isn't affected by the viruses found in cassava.

However, he said researchers should still be careful.

"We made the community aware that when they try to use such a system, they need to be a bit more careful," he said.

Mehta said it's important the results are being shared, even though they aren't the outcome for which they had hoped.

"Publishing negative results doesn't happen very frequently, so I was happy to see this was published," he said.

"A lot of the times in our field we try to emphasize the successes over the failures, but it's really the failures that allow us to move the field forward."