arXiv Machine Learning

When Genomic Masking Priors Fail to Transfer: Strong Variant Prediction, Weak Functional Generation

The paper introduces GenDA, a bidirectional discrete diffusion model designed for genomic sequence reconstruction, hypothesizing that entropy-guided span placement would improve variant-effect prediction and functional sequence generation. While the 202‑million‑parameter GenDA model achieves a higher ClinVar SNV AUROC (0.774) than a comparable autoregressive model, the improvement is not attributable to entropy guidance, and the model fails to outperform a shuffled‑gap baseline in zero‑shot functional inpainting across various genomic regions. The authors identify limitations such as tokenization granularity, span length caps, and the mismatch between local sequence complexity and functional importance, concluding that variant prediction, corruption priors, and functional generation are distinct tasks requiring separate validation.

arXiv AI
Sep 17

Structure is not mechanism: high-gain gated-FFN rows across text and genomic foundation models

The study investigates whether unusually high‑gain parameters in transformer models—specifically gated feed‑forward network (gated‑FFN) rows—play a critical functional role across both text and genomic foundation models. By computing exact bilinear weight operators and testing structural extremeness, the authors find that high‑gain rows are enriched for functional importance but do not reliably predict causal effect size or severity. The analysis reveals model‑specific causal organizations, including super‑additive interactions in DNABERT‑2 and position‑localized dependencies in GENERator, indicating that structural prominence signals enrichment rather than calibrated criticality.

By Alexandros Tzanakakis, Aris Karatzikos, Ilias Georgakopoulos-Soares
arXiv Machine Learning
Aug 27

Beyond Tokens: Probing Higher-Order Epistasis in Learned Protein Representations

The paper introduces ORBIT, a framework for probing higher‑order epistasis in protein representations. ORBIT validates Walsh‑based diagnostics on synthetic landscapes, then applies them to the GB1 fitness landscape, comparing several models including ridge regression, MLPs, and Residual Interaction Tokenization (RIT). While no architecture differences were found in overall prediction performance, RIT notably increased pairwise token‑level accessibility, and deeper MLPs improved higher‑order functional recovery, revealing representation‑level changes hidden by conventional metrics.

By Maryam Rahimimovassagh, Ivan Garibay, Niloofar Yousefi