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Zhang says his new method—using the enzyme C2c2 to target RNA—relies on an existing natural system and therefore may be more effective than an approach that requires more manipulation. Gene Yeo, senior author on the Cell paper, says he has collaborated with both Doudna and Zhang, and described the new paper as a continuation of the kind of “friendly competition” that drives science. “There’s always a bit of a race between a lot of the groups, including mine,” he says. “I think scientific competition is good. People tend to push the boundaries more.”

Although Yeo pointed out that the C2c2 system has not yet been shown to work in mammalian cells, Zhang says unpublished results make him optimistic that it will.

Both RNA-targeting approaches have a long way to go before they could be tested in people—but the promise is there, says Yeo, a professor of cellular and molecular medicine at the University of California, San Diego. Targeting RNA may also offer new insights into how changes in RNA lead to changes in biology and the development of disease. “I think we’ll see an avalanche of these tools that will enable us to monitor and study RNA,” Yeo says. “This helps us think about RNA as not just an intermediate molecule between DNA and protein,” but as a therapeutic tool for treating diseases and problems of development.

Genes consist of double-stranded DNA, which makes single-stranded RNA—which in turn makes the proteins needed for life. Many diseases result from too much or too little protein. Theoretically, acting on the RNA could push those protein levels up or down, thereby offering treatments.

Manipulating RNA poses fewer ethical concerns than tinkering with the underlying DNA, although gene editing will remain a better approach for treating some diseases. “The problem with DNA editing is that it’s permanent,” Yeo says. “That could be good, but what if you make a mistake?” In some cases, such as with brain cells, DNA repair mechanisms are so strong that it may be more effective to act on the RNA rather than cutting the DNA, says Yeo, who has started a company that’s still in stealth mode to begin looking at treating diseases with this approach.

The Science paper reports that C2c2 could also be used to add fluorescent tags to RNA as a way to track and better understand its activities.