REVIEW 3 major objections 5 minor 9 references
YOTO jointly learns a discrete top-k gene subset and a multi-task predictor in one differentiable model, claiming consistent gains in F1 over two-stage baselines and the non-sparse gradient baseline once panels reach 32 genes and above.
Reviewed by Pith at T0; open to challenge. T0 means a machine referee read the full paper against a public rubric. the ladder, T0–T4 →
T0 review · deepseek-v4-flash
2026-08-03 15:10 UTC pith:LBSECSKA
load-bearing objection A plausible method that overclaims: the end-to-end selection idea is sound, but the paper's own AUROC tables contradict the 'consistently outperforms' headline. the 3 major comments →
You Only Train Once: Differentiable Subset Selection for Omics Data
The pith
A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.
Core claim
YOTO is a single neural architecture that performs feature selection and prediction simultaneously. Each gene gets a learnable score; a differentiable permutation matrix derived from the Plackett–Luce ranking model turns those scores into a soft top-k selection, and a straight-through estimator makes the forward pass use a hard binary mask so that only the k selected genes reach the encoder and task heads. The prediction loss therefore backpropagates through the relaxed ranking, closing a feedback loop where the task guides selection and selection shapes representation. The central discovery claimed is that this closed loop, with exact sparsity during training, yields gene panels whose downs
What carries the argument
YOTO's engine is a differentiable permutation matrix derived from the Plackett–Luce ranking model, which converts learnable per-gene scores into a relaxed top-k selection; a straight-through estimator then forces the forward pass to use a hard binary mask so only k genes enter the shared encoder, while gradients flow back through the relaxed matrix. A temperature schedule sharpens the ranking over training, and k itself is annealed from all genes down to the target panel size. This construction is what lets selection and prediction be optimized together with exact sparsity present at inference.
Load-bearing premise
The load-bearing premise is that gradients computed through the relaxed top-k permutation accurately improve the hard discrete choice; the paper assumes the straight-through estimate of the gradient is a reliable optimizer of the true discrete objective, without measuring the discrepancy between the relaxed and hard selections.
What would settle it
Train YOTO on a synthetic dataset where a known set of 32 ground-truth informative genes is planted among thousands of noise features, keeping the rest of the pipeline unchanged. If the learned subset, evaluated by the same F1 metric, is not statistically distinguishable from a random or uniform top-k subset, or if the gradient signal for a gene outside the top-k does not align with whether that gene could plausibly enter the top-k, then the straight-through feedback loop is not doing the work claimed.
If this is right
- With panels of 32 genes or more on the visual-cortex benchmark, and at 64 genes on the COVID-PBMC benchmark, YOTO's F1 is at or above every baseline tested, and the gap widens as panel size grows.
- A single training run serves all tasks simultaneously (three per dataset), whereas baselines require three to six separate models for feature selection and prediction per task.
- No downstream classifier is needed: because the forward pass is truly sparse, the model's own prediction heads directly evaluate the selected panel, eliminating retraining.
- The ablation with identical architecture, single-task objective, and temperature schedule shows the sparse end-to-end selection module, not model size or multi-task supervision, drives the gains.
- The learned gene sets are claimed to capture interactions and complementarity among genes, not just individually informative markers, which is why performance improves more steeply as more genes are allowed.
Where Pith is reading between the lines
- A direct stress test would be to swap the Plackett–Luce permutation for independent Gumbel-Softmax top-k sampling; if performance holds, the exact ranking structure is not the active ingredient, pointing to the sparse mask itself.
- The straight-through mismatch could be diagnosed by measuring the gradient alignment between the hard-mask selection and the relaxed permutation at identical weights; low alignment would imply the training signal is a noisy proxy for the deployed discrete choice.
- Since the method's advantage appears only from 32 genes upward, the practical deployment window is spatial transcriptomics or targeted gene panels with at least that many measurements; the paper acknowledges the k=16 regime is not where YOTO wins.
- Turning the same closed loop toward an unsupervised or semi-supervised objective, such as reconstructing the full transcriptome from the selected genes, could produce interpretable biomarker panels without requiring any labels, an extension the paper does not test.
Editorial analysis
A structured set of objections, weighed in public.
Referee Report
Summary. The paper proposes YOTO, an end-to-end differentiable framework for joint gene subset selection and multi-task prediction in single-cell transcriptomics. Selection is performed by learning gene importance scores and applying a hard top-k mask in the forward pass while using a relaxed permutation matrix (based on the Plackett-Luce model) in the backward pass, enabling gradient-based training of the discrete selection. The authors evaluate on two datasets (mouse VISp spatial transcriptomics and COVID-PBMC scRNA-seq), comparing against Seurat, mRMR variants, Block HSIC Lasso, and PERSIST, and report F1, accuracy, AUROC, and AUPRC across subset sizes k = 16–256. The central claim is that YOTO "consistently outperforms state-of-the-art baselines" while providing a single-model multi-task solution.
Significance. If the claims were fully supported, the contribution would be practically valuable: a single-stage, sparse, end-to-end feature selector with a built-in classifier eliminates the two-stage pipeline overhead, and the multi-task formulation allows partially labeled datasets to share information. The paper includes a well-motivated ablation isolating the selection module, reports results over three seeds, and examines multiple imbalanced-classification metrics. However, the paper's own tables do not support the "consistently outperforms" claim, and at several evaluated subset sizes and metrics YOTO is clearly worse than baselines. The overstated central claim, together with the lack of any diagnostic for the straight-through gradient approximation, requires revisions before the paper can be accepted.
major comments (3)
- [Abstract and §4.4.1, Tables 5 and 6] The abstract's claim that YOTO "consistently outperforms state-of-the-art baselines" is contradicted by the paper's own results. On VISp at k=16 (Table 5) YOTO achieves F1 64.0±4.0 versus PERSIST 74.3±0.8 and mRMR-rf 67.2±1.6; on COVID-PBMC (Table 6) YOTO is second at k=16 (71.5 vs. mRMR-f 78.0) and at k=32 (79.5 vs. 81.7). The text acknowledges only "one notable exception" at small panel sizes, but these are multiple settings where YOTO trails. The claim needs to be weakened to "competitive and often superior at moderate/larger panel sizes," or the experiments and analysis need to be expanded to justify the original wording.
- [§4.4.3, Tables 7 and 8] The robustness claim across metrics is undermined by the AUROC results. At k=64 on VISp (Table 7), YOTO's AUROC is 91.9±0.1 while mRMR-rf and Block HSIC Lasso reach 99.9±0.0. On COVID-PBMC (Table 8), YOTO's AUROC is 80.9±0.2 versus 98.3±0.2 for mRMR-f and 95.8±0.1 for PERSIST — a 17-point gap. The text describes this as "slightly lower," which is a mischaracterization. Since AUROC is a standard metric for imbalanced classification and the paper claims robustness across metrics (§4.4.3), the paper must either report these results honestly, provide a concrete reason why AUROC is not informative here beyond a general expectation, or revise the claim.
- [§3.1, Eq. (3) and straight-through estimator] The entire method rests on the unpublished assumption that the straight-through estimator (hard forward mask, relaxed permutation matrix in the backward pass) provides a faithful gradient signal for the discrete top-k selection. The paper provides no analysis, diagnostic, or comparison of the learned score rankings against the performance of the hard mask. For example, one could test whether the selected genes at convergence are stable across seeds or whether the relaxed gradients mis-credit non-selected genes; the k=16 underperformance may reflect this mismatch. Since the method is not derivable as a proper estimator for the discrete objective, a correctness-risk concern remains. The authors should add at least one diagnostic or a formal argument that the relaxed gradient correlates with the true discrete selection objective.
minor comments (5)
- [Tables 5–8 and Figure 2] The tables and figure use inconsistent formatting: 'celltype5' in the text and 'celltype5' in Table 8 caption, but 'celltype5' in Table 6; also 'cell_types_25' appears as a task name. The method row is labeled 'Ours' in tables but the paper name is YOTO; unify terminology.
- [§4.4.1 and Figure 2] Figure 2 omits Seurat and mRMR-f 'due to consistently low performance,' but these baselines appear in Tables 5 and 6 and are discussed. Omitting them makes the figure less complete; it would be clearer to include all baselines or state explicitly that only a subset is shown for visual clarity.
- [§3.1, Eq. (2)] The notation π(s) is used both for the differentiable permutation matrix and as an argument in P(π(s)), which is confusing because π(s) is a matrix, not a permutation. Use different symbols, e.g., M(s) for the matrix.
- [§4.4.4, Table 4] The ablation says 'temperature parameters' are identical, but no temperature schedule is specified. Provide the annealing schedule or a reference to where it is given, so the equivalence is verifiable.
- [Appendix A.2] Tables 7 and 8 are presented as extended results but are crucial for the AUROC discussion in §4.4.3; consider moving them to the main text or explicitly cross-referencing them earlier.
Circularity Check
No circularity: YOTO is an empirical learning method whose selection scores are trained and evaluated on held-out data; same-group citations are descriptive, not load-bearing.
full rationale
YOTO's derivation chain is an empirical training procedure, not a set of analytical results that could reduce to their inputs. The learnable gene scores s are parameters; the forward pass applies the hard top-k mask Γ_k(s) (Eq. 3), and the task losses L_t (Eqs. 4-5) backpropagate through the relaxed permutation matrix π(s) (Eq. 1) to update both the encoder and the scores. The selected subset is therefore optimized against prediction loss on training data and evaluated on a held-out 80-20 split, which is standard supervised feature selection rather than circular reasoning. The paper's references to Sutter et al. 2023a/b, which share authors with the present work, are used only to describe the inspiration for the differentiable ranking module ('We employ a differentiable feature selection mechanism, inspired by the Differentiable Random Partition Model (DRPM, Sutter et al., 2023a)'); the implemented permutation matrix is attributed to Grover et al. 2019 and the straight-through estimator to Bengio et al. 2013, both external. No uniqueness theorem, fitted quantity renamed as a prediction, or definitional equivalence is used. The apparent inconsistency between the prose claim of 'consistently outperforming state-of-the-art baselines' and the reported AUROC values (e.g., Table 8 shows YOTO at 80.9±0.2 vs mRMR-f at 98.3±0.2, described as 'slightly lower') is a correctness/overclaiming concern, not a circularity concern, because the reported numbers are empirical results rather than quantities forced by construction.
Axiom & Free-Parameter Ledger
free parameters (3)
- gene importance scores s =
learned per gene, not reported
- subset size k =
16, 32, 64, 128, 256
- temperature schedule tau =
not reported
axioms (3)
- standard math The differentiable permutation matrix pi(s) from Grover et al. (2019) provides a valid relaxation of the top-k ranking operator.
- ad hoc to paper The straight-through estimator gives a faithful gradient signal for the discrete selection.
- domain assumption The HVG preprocessing and binarization choices are appropriate for all methods compared.
read the original abstract
Selecting compact and informative gene subsets from single-cell transcriptomic data is essential for biomarker discovery, improving interpretability, and cost-effective profiling. However, most existing feature selection approaches either operate as multi-stage pipelines or rely on post hoc feature attribution, making selection and prediction weakly coupled. In this work, we present YOTO (you only train once), an end-to-end framework that jointly identifies discrete gene subsets and performs prediction within a single differentiable architecture. In our model, the prediction task directly guides which genes are selected, while the learned subsets, in turn, shape the predictive representation. This closed feedback loop enables the model to iteratively refine both what it selects and how it predicts during training. Unlike existing approaches, YOTO enforces sparsity so that only the selected genes contribute to inference, eliminating the need to train additional downstream classifiers. Through a multi-task learning design, the model learns shared representations across related objectives, allowing partially labeled datasets to inform one another, and discovering gene subsets that generalize across tasks without additional training steps. We evaluate YOTO on two representative single-cell RNA-seq datasets, showing that it consistently outperforms state-of-the-art baselines. These results demonstrate that sparse, end-to-end, multi-task gene subset selection improves predictive performance and yields compact and meaningful gene subsets, advancing biomarker discovery and single-cell analysis.
Figures
Reference graph
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discussion (0)
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