crispr gene editing
Americans are okay with gene editing human embryos, as long as the tweak will cure a harmful genetic disease the baby is destined to get. Screenshot; video by McGovern Institute for Brain Research at MIT

The CRISPR genetic editing technique targets a series of repeated DNA sequences found in the genetic code of all sorts of organisms, from bacteria to humans. Special enzymes can find these repeated phrases and snip the DNA strands there; the cell then naturally stitches up the damaged DNA, so the organism can keep using it. But the method still isn’t perfect—mistakes still happen more often than researchers would like. Now a team of biologists, led by researchers from the Broad Institute of MIT and Harvard, have found a tiny molecule that, when used with CRISPR, may make the editing process more precise, according to a study published last week in Cell.

Most researchers editing DNA using the CRISPR system have relied on the Cas9 enzyme to snip the DNA. Cas9 isn’t the only enzyme that can do this—it just happens to be the one that scientists have found easiest to use. But Cas9 is really large, which means it’s hard to deploy in mature cells, and it’s not always as exact as researchers would like. So the biologists behind the study started looking for similar enzymes in various types of bacteria. They found one type called Cpf1 that was present in 16 different bacteria, and they discovered that two of these would work to edit human DNA.

Cpf1 works a bit differently than Cas9. Cpf1 cuts DNA at different spots than Cas9, and cleaves the two strands to be different lengths. This makes the editing process easier to control and could create new possibilities for how scientists can edit DNA in the future, as Nature News reports.

Though the Cpf1 system has some advantages over Cas9, the researchers aren’t yet sure if Cpf1 will become more popular. It could certainly offer new possible locations for DNA insertion, which has been a challenge in the past. That could mean rapid advances for genetic manipulation not only in plants and pests, but also for therapeutic benefits in humans.

If researchers can edit DNA more reliably, will they find as much of a backlash from those skeptical of its ethical use on human embryos? Probably. But the research also shows that biologists have only scratched the surface for what CRISPR (and its accompanying enzymes) can do, and that there may be many other enzymes out there that researchers have not yet discovered.