---
license: mit
language:
- en
tags:
- genomics
- dna
- virus
- bioinformatics
- metagenomics
- sequence-classification
- giant-virus
- mistral
pipeline_tag: text-classification
---

# GenomeOcean Main Classifier

A GenomeOcean 100M v1.2 fine-tuned sequence classifier that splits genomic
FASTA contigs into three broad biological categories:

| Label | Meaning |
|---|---|
| `Cellular` | Sequences derived from cellular organisms (eukaryotic, bacterial, archaeal, mitochondrial, plastid) |
| `NCLDV/Mirus` | Candidate Nucleocytoviricota (giant virus) or Mirus sequences |
| `Other Viruses` | Phages and other viral sequences outside NCLDV/Mirus |

This model is the **first stage** of a two-stage hierarchical Giant Virus
classifier. Contigs predicted as `NCLDV/Mirus` here are meant to be passed
to the companion [hyejong/genomeocean-sub-classifier](https://huggingface.co/hyejong/genomeocean-sub-classifier)
model, which further splits them into `NCLDV` and `Mirus`. Full pipeline
code, preprocessing details, and CLI tooling are available at
[Genomeocean_Giant_Virus_Classifier](https://github.com/hyej0ng/Genomeocean_Giant_Virus_Classifier)
on GitHub.

## Model architecture

- Base: GenomeOcean 100M v1.2, a Mistral-architecture genomic language model,
  fine-tuned for sequence classification (`MistralForSequenceClassification`).
- Hidden size 768, 12 layers, 8 attention heads, vocab size 4,096,
  max position embeddings 32,768.
- Custom modeling code (`modeling_mistral.py`, `configuration_mistral.py`) is
  included in each fold folder, so loading requires `trust_remote_code=True`.

## 5-fold ensemble

This repository hosts **five independently fine-tuned folds**
(`fold1` – `fold5`), each in its own subfolder with a full set of model,
tokenizer, and config files. The recommended way to use this model is to
run all five folds on the same input and average (soft-vote) the softmax
probabilities — this is what the reference pipeline below does
automatically. A single fold can also be used on its own, at the cost of
losing the variance/agreement signal the ensemble provides.

## Input format

Inputs are 5,000 bp genomic chunks derived from FASTA contigs, preprocessed
as follows before tokenization:

1. Convert the sequence to uppercase.
2. Remove characters other than `A`/`C`/`G`/`T`/`N`.
3. Remove `N`.
4. Split the cleaned sequence into 5,000 bp windows with a 5,000 bp stride
   (non-overlapping).
5. Contigs shorter than 5,000 bp, and the incomplete tail of longer contigs,
   are not used for prediction.

Tokenization uses the fold's own tokenizer with `max_length=1250`.

## Usage

### Recommended: reference CLI package

The GitHub repository ships an installable CLI (`genomeocean-main`) that
handles FASTA parsing, chunking, batching, 5-fold ensembling, and result
aggregation for you:

```bash
git clone https://github.com/hyej0ng/Genomeocean_Giant_Virus_Classifier.git
cd Genomeocean_Giant_Virus_Classifier
python -m pip install -r requirements.txt
python -m pip install ./genomeocean-main-classifier

genomeocean-main predict \
  --input /path/to/input.fasta \
  --output-dir /path/to/results \
  --model-id hyejong/genomeocean-main-classifier \
  --subfolder fold1 --subfolder fold2 --subfolder fold3 \
  --subfolder fold4 --subfolder fold5 \
  --device cuda
```

See the [Main Classifier README](https://github.com/hyej0ng/Genomeocean_Giant_Virus_Classifier/blob/main/genomeocean-main-classifier/README.md)
for the full CLI reference, or the
[Integrated Pipeline README](https://github.com/hyej0ng/Genomeocean_Giant_Virus_Classifier/blob/main/genomeocean-classifier-pipeline/README.md)
to run Main and Sub together and get final `Cellular` / `NCLDV` / `Mirus` /
`Other Viruses` labels in one command.

### Direct `transformers` usage (single fold)

```python
import torch
from transformers import AutoModelForSequenceClassification, AutoTokenizer

model_id = "hyejong/genomeocean-main-classifier"
fold = "fold1"

tokenizer = AutoTokenizer.from_pretrained(model_id, subfolder=fold, trust_remote_code=True)
model = AutoModelForSequenceClassification.from_pretrained(
    model_id, subfolder=fold, trust_remote_code=True
)
model.eval()

id2label = {0: "Cellular", 1: "NCLDV/Mirus", 2: "Other Viruses"}

sequence = "ACGT..."  # a single, already-preprocessed 5,000 bp chunk
inputs = tokenizer(sequence, return_tensors="pt", truncation=True, max_length=1250)
with torch.inference_mode():
    probs = torch.softmax(model(**inputs).logits, dim=-1)[0]

predicted = id2label[int(probs.argmax())]
print(predicted, probs.tolist())
```

To reproduce the full 5-fold ensemble manually, repeat the above for
`fold1` – `fold5` and average the resulting probability vectors before
taking the `argmax`.

## Training data

Trained on metagenome-derived genomic contigs/fragments:

| Label | Scope |
|---|---|
| `Cellular` | Eukaryotic, bacterial, archaeal, mitochondrial, and plastid sequences |
| `NCLDV/Mirus` | Full NCLDV and full Mirus sequences |
| `Other Viruses` | Phages and other viruses |

## Limitations

- Confidence scores are hierarchical/comparative, not calibrated
  probabilities of biological truth.
- Sequence length, assembly quality, and distance from the training
  distribution can affect predictions; ensemble agreement across folds
  (`ensemble_agreement`, `confidence_std` in the reference pipeline output)
  should be checked for low-confidence or borderline calls.
- For final NCLDV vs. Mirus resolution, pair this model with
  [hyejong/genomeocean-sub-classifier](https://huggingface.co/hyejong/genomeocean-sub-classifier).

## License

MIT