bioRxivSynthetic BiologyPreprint
Design of highly functional genome editors by modeling the universe of CRISPR-Cas sequences
Jeffrey A. RuffoloiD, Stephen NayfachiD, Joseph P. GallagheriD, Aadyot Bhatnagar, Joel Beazer, Riffat Hussain, Jordan Russ, Jennifer Yip, Emily HilliD, Martin PačesaiD, Alexander J. MeeskeiD, Peter CameroniD, Ali MadaniiD
Abstract
Gene editing has the potential to solve fundamental challenges in agriculture, biotechnology, and human health. CRISPR-based gene editors derived from microbes, while powerful, often show significant functional tradeoffs when ported into non-native environments, such as human cells. Artificial intelligence (AI) enabled design provides a powerful alternative with potential to bypass evolutionary constraints and generate editors with optimal properties. Here, using large language models (LLMs) trained on biological diversity at scale, we demonstrate the first successful precision editing of the human genome with a programmable gene editor designed with AI. To achieve this goal, we curated a dataset of over one million CRISPR operons through systematic mining of 26 terabases of assembled genomes and meta-genomes. We demonstrate the capacity of our models by generating 4.8x the number of protein clusters across CRISPR-Cas families found in nature and tailoring single-guide RNA sequences for Cas9-like effector proteins. Several of the generated gene editors show comparable or improved activity and specificity relative to SpCas9, the prototypical gene editing effector, while being 400 mutations away in sequence. Finally, we demonstrate an AI-generated gene editor, denoted as OpenCRISPR-1, exhibits compatibility with base editing. We release OpenCRISPR-1 publicly to facilitate broad, ethical usage across research and commercial applications.
- organism: human
- assay: CRISPR screen
- research focus: drug response / drug discovery
- approach: large language model
Abstract summary
Claude Opus 5.5 · xhigh effort · 18 Oct 2026 · from the abstract · CC BY-NC-ND 4.0
Language models trained on over one million mined CRISPR operons generated Cas9-like effectors and matching guide RNAs, and an AI-designed editor is reported to edit the human genome precisely.
CRISPR effectors taken from microbes often lose activity or specificity once moved into settings such as human cells, and natural sequence diversity bounds what can be picked off the shelf. Generative sequence models trained across CRISPR-Cas diversity are presented as a way to leave that natural repertoire behind and still obtain a functional human-genome editor.
Key results
ClaimedA gene editor produced by generative models is reported to perform precision editing of the human genome, described as the first such demonstration for an AI-designed editor.
Stated as a demonstration; the abstract gives no editing efficiencies, target loci, cell types or comparison numbers for this claim. · Abstract
ShownThe generative models expand CRISPR-Cas sequence space well beyond the natural repertoire and also design the companion guide RNAs.
4.8x as many protein clusters across CRISPR-Cas families as are found in nature, from models trained on a curated set of more than one million CRISPR operons mined from 26 terabases of assembled genomes and metagenomes; single-guide RNA sequences were tailored for Cas9-like effectors. · Abstract
ClaimedSeveral designed editors are claimed to match or beat SpCas9 on activity and specificity despite being far from it in sequence, and OpenCRISPR-1 is reported to work in a base-editing context.
Described as comparable or improved relative to SpCas9 while 400 mutations away in sequence; no activity, specificity or base-editing measurements are reported in the abstract. · Abstract
Methods, data and reproducibility
CRISPR operons were mined systematically from assembled genomes and metagenomes to build a training corpus, large language models were trained on these sequences to generate novel Cas effector proteins and matched single-guide RNAs, and selected designs were tested experimentally for editing in human cells and for base-editing compatibility.
- Curated dataset of CRISPR operons mined from assembled genomes and metagenomes (26 terabases searched) · n = over one million CRISPR operons
- Human-genome editing with an AI-designed programmable editor, and a base-editing test of OpenCRISPR-1 · human
- Methods & tools
- large language models, OpenCRISPR-1, SpCas9, base editing
- Reproducibility gaps
- OpenCRISPR-1 is said to be released publicly for research and commercial use, but the abstract gives no repository, licence terms or accession.
Limitations (2)
- Activity, specificity and base-editing performance are asserted without numbers, so how close the designed editors come to SpCas9 cannot be judged from the abstract. · noted in this summary
- No URL or accession is given for OpenCRISPR-1, the model weights or the mined operon dataset, despite the stated public release. · noted in this summary
Read this if you design proteins with sequence models or choose Cas effectors, and want to know how far generated editors are claimed to be from natural CRISPR diversity.
- Citations
- 90
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