Octopuses are incredibly clever creatures. They can open jars, solve mazes and even use tools. One species, the common blanket octopus, wields venomous tentacles ripped from the Portuguese man o’ war as weapons.

Now, researchers have discovered a mysterious mutation in some octopuses that might explain their intelligence. A study published in the August 17 issue of the journal Current Biology reveals that the eight-limbed creatures can produce proteins with extreme accuracy thanks to a variation never seen in any other animal. Although there is no direct evidence that the adaptation is linked to expanded octopus brainpower, only a lineage of creatures with enlarged nervous systems and that can carry out complex behaviors appears to have the mutation.

Scientists made this discovery by accident. About five years ago, study co-author Richard Han, then a graduate student at Harvard Medical School, was examining molecules called ribosomal RNA (rRNA) in tissues from the California two-spot octopus. The molecules create a 3D scaffold for ribosomes, the cells’ protein factories.

Many sequences of rRNA remain pretty much the same across all known animals. But Han noticed something unusual in those from the octopus: an unexpected gap that broke what’s usually one rRNA fragment in other creatures into two.

“We figured we were bad at extracting RNA” and simply had made a mistake, says study co-author Nicholas Bellono, a molecular biologist at Harvard, to Sara Reardon at Science.

Further tests, however, confirmed that something else was going on. Inserting the same break in the ribosomes of Escherichia coli bacteria made the engineered cells produce proteins with about twice their usual accuracy.

To examine when the strange rRNA feature evolved, the team compared two groups of octopuses that diverged more than 100 million years ago: incirrates, shallow-water octopuses with developed nervous systems that support complex behaviors, and cirrates, deep-sea creatures with simpler nervous systems adapted for slow swimming and passive feeding.

The rRNA break was present in all five examined incirrate species, the team found. But a sample from a cirrate—specifically, a dumbo octopus—lacked the gap. Squids, which diverged from octopuses about 300 million years ago, also didn’t have it.

The findings hint that the rRNA adaptation might be connected to the evolution of the shallow-water octopuses’ large nervous systems. Their brains—which are spread throughout their bodies—had to expand quickly as they learned to keep up with predators and increased competition in this environment. Nerve cells, or neurons, are long-lived, study co-author Rishav Mitra tells Scientific American’s Cody Cottier, which means protein misfolding is particularly bad for them. By preventing that, the rRNA break “might help these neurons to work well,” he adds.

“The major surprise is that the ribosome, which is highly conserved across life, can actually undergo evolutionary changes that impact function, and may even contribute to new innovations” study co-author Amy Lee, a cell biologist at Harvard, says in a statement.

Joshua Rosenthal, a molecular biologist at the Marine Biological Laboratory who wasn’t involved in the work, calls the discovery “super interesting,” although he notes that more research is needed to prove whether the rRNA change drove the evolution of sophisticated brains and behaviors. “We’re just getting to the beginning of genetics with these organisms,” he tells Science.

The study authors suspect their findings may lead to potential therapies for neurodegenerative diseases like Alzheimer’s disease and Parkinson’s disease that involve misfolded proteins in the brain. Lee tells Scientific American that she hopes that it will be possible to design drugs that copy the octopus mutation for accurate protein synthesis.

If we “use nature as a guide to understand how that happens naturally,” she says, “then we can probably find ways to put it into human cells.”