IsoAlign: Isoform-Aware DNA-Protein Alignment via Joint-Embedding Predictive Architectures
Authors: Niousha Sadjadi, Arman Seyed-Ahmadi, Tony Tu, Micaela Elisa Consens, Kerr Ding, Alif Munim, Lila Kari, Zehui Li, Barry B. Rubin, Bo Wang, Vallijah Subasri
Organizations: University of Waterloo · Peter Munk Cardiac Centre, University Health Network · Georgia Institute of Technology · University of Toronto · Imperial College London · Vector Institute
Genomic foundation models (GFMs) have emerged as a powerful paradigm for learning DNA sequence representations, yet existing self-supervised pretraining strategies overlook alternative splicing and underperform compared to specialized models. To address this gap, we introduce IsoAlign, a multimodal framework that grounds genomic pretraining in isoform-aware DNA-protein alignment to learn biologically meaningful representations. IsoAlign aligns transcripts to their corresponding protein isoforms, capturing both coding sequences and broader regulatory contexts, using two Joint-Embedding Predictive Architectures (JEPA): DNA-Protein JEPA (DP-JEPA), which predicts protein representations from DNA using contrastive alignment, and Isoform-Masked JEPA (IM-JEPA), which models relationships among alternative isoforms of the same gene through masked protein prediction. We evaluate the learned DNA representations of these architectures across a multi-metric evaluation suite spanning tasks, including the prediction of pathogenicity, fitness, gene expression, and TF binding. Our results demonstrate that isoform-aware cross-modal alignment using JEPA significantly improves functional representations and downstream performance, establishing a promising direction for GFM pretraining.
Figures & tables
Figure 1: IsoAlign JEPA Architectures
Figure 2: DMS Fitness Prediction. Spearman correlation between embedding-based variant scores and fitness scores on Deep Mutational Scanning (DMS) datasets. Models are grouped by category: DNA FMs (gray), Protein FMs (red), and IsoAlign models (blue). IsoAlign consistently outperforms unimodal DNA baselines, demonstrating that cross-modal pretraining with protein-derived inductive biases improves variant effect prediction without task-specific fine-tuning.
ClinVar Splicing
MFASS
Model
Params
Cosine
ℓ2
Cosine
ℓ2
DNABERT-2 ( Zhou et al., 2023 )
117M
0.14
0.15
0.04
0.04
JEPA-DNABERT-2 ( Larey et al., 2026 )
117M
0.14
0.15
0.04
0.04
HyenaDNA-tiny ( Nguyen et al., 2023 )
0.44M
0.16
0.15
0.04
0.04
JEPA-HyenaDNA-tiny
0.44M
0.15
0.16
0.04
0.04
Caduceus-PH ( Schiff et al., 2024 )
7.7M
0.20
0.18
0.04
0.04
Table 1: Variant effect prediction from DNA representations, evaluated by AUPRC using two metrics. Values in parentheses indicate changes relative to the parent DNA model; underlined values indicate the best performance per column, and bold values are the best IsoAlign model per backbone.
Model
Training
Params
AUROC
AUPRC
LucaOne ( He et al., 2025 )
LoRA
1.8B
0.785 ± 0.001
0.778 ± 0.002
BPNet ( Avsec et al., 2021 )
Full
0.12M
0.861 ± 0.004
0.851 ± 0.003
ChromBPNet ( Pampari et al., 2023 )
Full
6M
0.867 ± 0.005
0.851 ± 0.007
AlphaGenome ( Avsec et al., 2026 )
Full
450M
0.892 ± 0.002
0.879 ± 0.003
IsoAlign
LoRA
650M
0.934 ± 0.001
0.928 ± 0.001
Table 2: TFLink transcription factor binding prediction (mean ± SD over 4 training seeds).
Table 4: Deep Mutational Scanning dataset statistics.
Stratification
Categories
Samples
Binding Status
Positive
100,000
Negative (same-family)
100,000
Binding Site Length
Short ( ≤ 12 bp)
111,982
Medium (13–20 bp)
78,807
Long ( > 20 bp)
9,211
TF Family
TF_bZIP
70,000
Appendix
Table 5: TFLink Evaluation Dataset
ClinVar Splicing
MFASS
Model
Params
Cosine
ℓ2
CLS
Mul
Cosine
ℓ2
CLS
Mul
Baselines
DNABERT-2 ( Zhou et al., 2023 )
117M
0.14
0.15
0.18
0.18
0.04
0.04
0.05
0.04
JEPA-DNABERT-2 ( Larey et al., 2026 )
117M
0.14
0.15
0.27
0.19
0.04
0.04
0.08
0.04
HyenaDNA ( Nguyen et al., 2023 )
6.6M
0.17
0.18
0.25
0.18
0.04
0.04
0.05
0.04
HyenaDNA-tiny
0.44M
0.16
0.15
0.22
0.17
0.04
0.04
0.04
0.04
Appendix
Table 6: Variant effect prediction evaluation on ClinVar Splicing and MFASS using four metrics. Underlined values indicate the best performance per column, and bold values are the best IsoAlign model per backbone.
Model
VEP window ( L )
Reason
LucaOne / LucaOne-gene
4,094
max_pos_embeddings =4096
AIDO.DNA-300M
3,998
max_pos_embeddings =4000
NTv3-650M / 100M, JEPA-NTv3-100M
4,096
U-Net 7-downsample (must be ÷128 )
Omni-DNA-116M / 300M
1,200
250 BPE-token context cap
Appendix
Table 7: Per-model VEP context-window deviations from the default.
Parameter
DP-JEPA
IM-JEPA
Contrastive
MLM
Batch size (per GPU)
16–32
8
16
16
Gradient accumulation
4
8
4
4
Effective batch size
256
256
256
256
Learning rate
1e-5
1e-5
1e-5
1e-4
Max epochs
150
150
150
150
Appendix
Table 8: Training hyperparameters by objective.
Objective
Runs
Wall-Clock (h)
GPU-Hours
DP-JEPA
34
274
1,097
IM-JEPA
12
136
543
Contrastive
48
368
1,474
MLM
11
63
254
Total
71
568
2,270
Appendix
Table 9: Total compute used for pretraining experiments.