Genome World Model
Shanghai Artificial Intelligence Laboratory

Technical report

One model that reads, scores, and writes DNA at genome scale.

CENO is a genome-scale world model. Instead of building a separate tool for each task, CENO uses one long-context autoregressive model to understand long DNA, score the effect of mutations, and design new regulatory sequences.

Understand · long context Evolve · variant effects Design · regulatory DNA
CENO Team Shanghai Artificial Intelligence Laboratory

The approach

One backbone, three stages: pre-train, evolve, design

A genomic world model keeps nucleotide-level state over very long sequences and exposes one likelihood interface. That single interface is what lets the same model perform four reusable operations over genome sequence space — completion, perturbation, conditioning, and design.

Context length 8k → 1M tokens
8k 131k 1M
  1. 01

    Pre-train

    Learn DNA grammar at scale

    A hybrid Mamba + sparse-attention + mixture-of-experts backbone is trained at 300M / 600M / 1B parameters, with a staged curriculum from 8k tokens up to 1M-token whole-genome context.

  2. 02

    Evolve

    Add evolutionary evidence

    Post-training on packed real multiple-sequence alignments lets CENO score reference vs. mutant alleles under shared homologous context — turning likelihood into variant-effect prediction.

  3. 03

    Design

    Generate functional DNA

    A CENO-based accessibility oracle guides conditional generation and reinforcement learning to design cell-type-specific enhancers in mouse cortex.

CENO at a glance

1M tokens of long-context continuation (up to 1,048,576)
3 sizes 300M / 600M / 1B parameters, one staged curriculum
~8× faster long-context generation than Evo 2, with no out-of-memory failures
1 interface one likelihood for completion, perturbation, conditioning, and design
Stage 01 · Understand

Reading DNA across megabase-scale context

With long-context training, CENO keeps track of distant sequence and — with no task-specific fine-tuning — develops attention that lines up with genome annotations and chromatin boundaries.

Figure 2 — retrieval and chromatin-scale readouts under extended context.
0.96 mean AUROC on human TAD-boundary probes (CENO 600M at 131k), from frozen representations.
131k context at which distal needle-retrieval and TAD-scale attention patterns emerge.
Zero-shot annotation- and boundary-linked attention appears without any task-specific fine-tuning.
Stage 02 · Evolve

Turning likelihood into variant-effect prediction

Post-training on real multiple-sequence alignments lets CENO compare a reference and a mutant allele under the same evolutionary context. The gap in likelihood becomes a direct read-out of variant impact.

Figure 4 — evolutionary context improves matched variant-effect scoring.
+46.4pp largest matched BRCA1 AUPRC gain from MSA post-training (CENO 600M) vs. the pre-MSA checkpoint.
BRCA1/2 improved matched variant-effect prediction on clinically important genes.
Cross-species strong evolutionary-enrichment signal from reference−mutant likelihood deltas.
Stage 03 · Design

Designing cell-type-specific enhancers

The same model powers generation. A CENO-based accessibility oracle scores candidate sequences, and reinforcement learning steers conditional generation toward enhancers that are active in the target cell type.

Figure 5 — accessibility oracle, motif grammar, and generated enhancer specificity.
0.81 / 0.75 oracle Pearson / Spearman for held-out cell-type ATAC prediction.
Mouse cortex cell-type-conditioned enhancer generation with oracle-guided reinforcement learning.
Specific generated regulatory elements match or exceed the cell-type specificity of natural ones.

Capability

Writing genome-scale sequence

The same pretrained backbone also completes and writes DNA. Withheld-sequence recovery improves with model scale and long-context training, and the 1 Mb context reaches into chromatin-loop and TAD-scale structure — run efficiently on the vLLM inference stack.

CENO 1B ≈ Evo 2-7B Gene-scale recovery across eukaryotic, bacterial, and archaeal species — matching a 7B model with far fewer parameters.
Beyond imitation Generated sequences preserve codon usage, gene-coding density, and gene order/synteny rather than copying natural DNA — evidence CENO learns genomic grammar.
1 Mb context Megabase generation captures chromatin loops and TAD-scale structure at representative loci such as MYC and PAX.

Benchmark

Zero-shot variant effects across ten task families

A single pretrained likelihood-delta score is evaluated against roughly fifty published genome models, spanning splice variants, BRCA1/BRCA2, TraitGym, ClinVar, causal eQTLs, expression perturbation, enhancer–gene links, structural variants, molecular fitness, and metabolic pathways.

#1CENO 1B · 1M context
#2CENO 1B · 131k context

Top two of the filtered cross-family ranking, ahead of Evo 2 40B at #3.

  • Structural-variant deletions — CENO 1B takes the top three (AVG2 up to 0.633).
  • Pathogenic ClinVar SNVs — three CENO 1B checkpoints trail only Evo 2 40B (AUROC to 0.914).
  • Causal eQTLs — CENO 1B leads the nearest variant-to-TSS bin (AUROC 0.669).
Compared against
  • Evo 2 (7B / 40B)
  • Nucleotide Transformer
  • Caduceus
  • HyenaDNA
  • DNABERT
  • GENERator
  • Genos
  • GPN
  • Grover
  • OmniReg-GPT
Figure 3 — cross-family zero-shot ranking and task-specific read-outs.

Paper & resources

Read the report and cite CENO

First page preview of the CENO technical report
Technical report PDF CENO: A Genome-Scale World Model for Evolutionary Sequence Interpretation and Programmable Regulatory Design

This page hosts the report directly and provides a stable project URL. The released code, model checkpoints, and benchmark artifacts are available through the links below.

Citation
@misc{ceno2026,
  title  = {CENO: A Genome-Scale World Model for
            Evolutionary Sequence Interpretation and
            Programmable Regulatory Design},
  author = {Ma, Mingqian and Wu, Yucheng and Chen, Xin and Jiang, Feifei and
            Lin, Peijun and Ye, Dongxin and Sun, Yidi and Zhang, Yijing and
            Shi, Tianqiong and Zhao, Yu and Ouyang, Wanli and Zhou, Bowen and
            Bai, Lei and Ren, Yuchen},
  year   = {2026},
  note   = {Technical report}
}