Summary
Anthropic says Claude agents identified a previously uncharacterised system in bacteriophages, built around a reverse transcriptase and an array of DNA repeats. Early lab experiments found that the array is expressed as distinct short RNAs; the system’s function is still under investigation.
Anthropic says Claude agents identified a previously uncharacterised enzyme system in bacteriophages, the viruses that infect bacteria. The system, which the company calls array-associated reverse transcriptases (ARTs), includes a reverse transcriptase, a neighbouring partner gene and a long array of regularly spaced DNA repeats. In early laboratory experiments, Anthropic researchers found that the array is expressed as distinct short RNAs. The system’s biological function is still being investigated.
The finding is notable because the reverse transcriptase itself was already known: earlier research had identified it in a jumbo phage. Anthropic says Claude drew attention instead to the features around it—the DNA repeat array and an accessory protein whose function is unknown. The proposed discovery is therefore a new association of genetic elements, not a newly discovered enzyme acting alone.
A repeat pattern beside a known enzyme
Reverse transcriptases copy RNA into DNA. They occur in diverse biological systems, including some that researchers have studied as part of bacterial immune defences. In this case, Claude’s agents searched DNA near genes for reverse transcriptases and noticed a tandem array of repeated sequences beside an unusual enzyme gene.
The arrangement recalls CRISPR arrays, which contain repeated DNA sequences interspersed with variable sequences. CRISPR systems can use RNA derived from these arrays to guide molecular machinery to specific genetic targets. Anthropic says the ART array also produces distinct short RNAs, a result that may help researchers investigate how the system works. The resemblance is a reason to study ART, but it does not by itself establish that ART has CRISPR’s function or can be used for gene editing.
Anthropic reports that ARTs are found mainly in bacteriophages. The company’s first experiments focused on the array’s expression; further experiments are under way to determine the system’s primary function. How its RNA, reverse transcriptase and partner protein interact remains central to understanding what the system does.
How Claude narrowed the search
Anthropic says the research group formed in spring 2026 to use AI models to identify unusual protein families in DNA data and test hypotheses in the laboratory. For this search, roughly 950 Claude agents worked for 21 hours, using 210 million tokens. The company says the agents gathered more than 200,000 reverse transcriptases, selected 3,500 candidate systems and narrowed these to 20 candidates for detailed analysis and human-readable reports.
One agent selected an unusual reverse-transcriptase family for closer examination and detected the nearby repeat pattern. It then counted the repeats, assessed their spacing, compared the arrangement with known systems and searched for previous reports before submitting its candidate for human review. Anthropic characterises scientists’ input as high-level direction and laboratory work; the company says human researchers performed all experiments.
This workflow shows how AI-assisted genome mining can help surface patterns for biological investigation. The evidence reported so far identifies an unusual system and shows that its repeat array produces short RNAs. Establishing the system’s biological role—and whether its components carry out any programmable operation—will depend on the ongoing experiments.