Anthropic says Claude identified a previously uncharacterized enzyme system called ART, found mainly in bacteriophages—viruses that infect bacteria. The company says its agents used 210 million tokens searching DNA data before flagging an unusual repeat pattern for human review and lab testing.

The underlying reverse transcriptase, an enzyme that copies RNA into DNA, was already known. Anthropic says Claude appears to be the first to notice the associated DNA repeats and accessory protein that define the system.

The company has released a preprint describing the findings. Although the repeats resemble CRISPR arrays, Anthropic says much more work is needed to determine ART’s function and whether it could have similar uses.