Cited by 260Bioinformatics and Genomic NetworksGene expression and cancer classificationGenomics and Phylogenetic Studies

The DOI matches its Crossref record; 45 of the 47 references it cites were found in a registry or an index; none of the 17 sources its claims cite is checked for support yet.

Guidance for RNA-seq co-expression network construction and analysis: safety in numbers

Open access
Ballouz, S., Verleyen, W., Gillis, J.·2015·Bioinformatics

Abstract

Motivation: RNA-seq co-expression analysis is in its infancy and reasonable practices remain poorly defined. We assessed a variety of RNA-seq expression data to determine factors affecting functional connectivity and topology in co-expression networks. Results: We examine RNA-seq co-expression data generated from 1970 RNA-seq samples using a Guilt-By-Association framework, in which genes are assessed for the tendency of co-expression to reflect shared function. Minimal experimental criteria to obtain performance on par with microarrays were >20 samples with read depth >10 M per sample. While the aggregate network constructed shows good performance (area under the receiver operator characteristic curve ∼0.71), the dependency on number of experiments used is nearly identical to that present in microarrays, suggesting thousands of samples are required to obtain ‘gold-standard’ co-expression. We find a major topological difference between RNA-seq and microarray co-expression in the form of low overlaps between hub-like genes from each network due to changes in the correlation of expression noise within each technology. Contact: jgillis@cshl.edu or sballouz@cshl.edu Supplementary information: Networks are available at: http://gillislab.labsites.cshl.edu/supplements/rna-seq-networks/ and supplementary data are available at Bioinformatics online.

Overview

AI snapshot

Written from the paper’s full text.

TL;DR

This paper benchmarks RNA-seq co-expression network construction against microarrays and finds that simple correlation-based networks, especially when aggregated across many datasets, recover known gene function comparably to microarrays. However, RNA-seq and microarray networks differ sharply in topology, largely because low-expression noise creates different hub genes.

Key findings

  • Individual RNA-seq co-expression networks performed modestly, with an average AUROC of 0.585; only 0.7% of GO terms averaged above 0.8 AUROC, and only 2% ever exceeded 0.9 AUROC in any assessed network.
  • Aggregating networks improved functional connectivity to about 0.71 AUROC for both RNA-seq and microarray data; roughly 20 experiments were enough for AUROC >0.6, while capturing unknown functional information may require more than 50 experiments.
  • RNA-seq and microarray aggregate networks had negatively correlated node degrees, and hub-like genes were significantly dissimilar between technologies (P < 1.4e-9), even though both captured individual GO functions similarly.
  • Low-expressing transcripts that failed SEQC reliability thresholds in at least 80% of experiments had high node degree in microarrays but low node degree in RNA-seq, explaining much of the topological mismatch.

Methods

  • The authors assembled 50 RNA-seq experiments totaling 1970 samples from SRA, Gemma, BrainSpan, and ReCount, plus 43 microarray experiments totaling 5134 arrays from GEO.
  • Expression was estimated with Cufflinks, RSEQtools, and RSEM; co-expression networks used rank-transformed correlation edge weights, with comparisons to mutual information, ARACNE, CLR, MRNET, and WGCNA thresholding.
  • Functional connectivity was assessed by guilt-by-association using neighbor voting and other machine-learning classifiers, with 3-fold cross-validation and AUROC against GO, KEGG, and Reactome annotations; aggregate networks were built by summing rank-standardized edges across datasets.

Limitations

  • Stated: the authors note that their use of GO as the definition of function is the most easily critiqued aspect, although KEGG and Reactome gave nearly identical results; they also state that they cannot readily assess RNA-seq in its most novel applications, such as novel or more diverse transcript assessment.
  • Stated: they do not claim to identify an ideal RNA-seq co-expression method, and they note that focused uses such as tissue-specific or developmental analyses may not be higher performing in their framework.
  • Evident: the study is limited to human datasets and existing annotations, ignores alternate isoforms in aggregates and performance measures, and uses median values when multiple measures exist, so isoform-level or cross-species generalization is not established.

Model-written summary. Check it against the paper before relying on it.

Integrity signals

Registry

Crossref · 10.1093/bioinformatics/btv118

Cites

45 of 45 references verified0 citation errors · 0 not checkable

Statistics

Nothing to recompute.

Verification

Claims the paper makes

0 of 17 cited sources checked · 0 supported · 0 flagged

  • It may state two separate claims as one. 33
  • Probably not a substantial claim. 6
36 of 36
  • The paper relies on this without support.

    RNA-seq co-expression analysis is in its infancy and reasonable practices remain poorly defined.

    “RNA-seq co-expression analysis is in its infancy and reasonable practices remain poorly defined.”
  • The paper relies on this without support.

    The GO, KEGG, and Reactome annotations used as labels accurately reflect gene function and are sufficiently complete for evaluating functional connectivity.

    “By using known annotations as labels for the genes (here we used GO, KEGG and Reactome labeled gene sets), one can determine how well the network recapitulates this information”
  • The paper relies on this without support.

    The 10 RNA-seq experiments selected for method comparisons are representative of the broader corpus.

    “We used a sample of 10 representative experiments, comparing the estimation expressions of Cufflinks, RSEQtools and RSEM and constructed co-expression networks using our default procedures”
  • The paper relies on this without support.

    The aggregate network's performance on GO terms is a valid proxy for capturing unknown functional information.

    “to comprehensively capture unknown functional information may require >50 separate experiments.”
  • The paper relies on this without support.

    The RNA-seq and microarray datasets used are comparable enough that observed differences in network topology and sample-size dependency reflect technology rather than dataset composition.

    “In a similar fashion, we generated an aggregate of the microarrays on a random sample of 30 datasets using 3320 individual microarrays.”
  • The paper relies on this without support.

    GO slim's 109 terms are broadly representative of the ontology overall.

    “For our machine learning analysis, we used GO slim, a version of GO that filters analyses to 109 GO terms, broadly representative of the ontology overall.”
  • The paper relies on this without support.

    The GO reference data adequately represents biological function for evaluating co-expression network performance.

    “our use of the GO as a way of defining 'function' is perhaps the most easily critiqued, albeit hard to avoid and common.”
  • The paper relies on this without support.

    The 50 RNA-seq and 30 microarray datasets are representative of their respective technologies.

    “We used the 30 networks from the microarray aggregate, and the 50 networks of the RNA-seq aggregates”
8 of 8

Claims other papers make about this one

Each is checked against this paper’s own text: does it say what the citing paper says it does?

Self-check

Percentages, sums and reported differences re-computed from the paper’s own numbers.

Each contradiction between two passages listed here was confirmed by an independent check.

  • Conflicting minimum read-depth guidance

    Major

    The abstract gives more than 10 million reads per sample as a minimum for performance comparable to microarrays. The results section says that even modest performance requires close to 100 million reads per sample, a substantially higher threshold.

  • Machine-learning method dependence is described in opposite ways

    Minor

    The results say the findings are not strongly independent of method, whereas the discussion says the selected algorithm has little influence on them.

  • Figure 4 correlation is labeled as a P-value in the text

    Minor

    The text assigns P = 0.84 to the similarity shown in Figure 4B, but the figure caption identifies 0.84 as the correlation and gives its P-value as less than 1e−16.

3 of 3

Citations

Cites

Flagged first, then by citations

Show all 47 references

2 of the 47 references couldn’t be matched to a known paper.

Cited by

Sorted by citations

See all 260

Metadata

Authors
Ballouz, S., Verleyen, W., & Gillis, J.
Affiliations
Cold Spring Harbor Laboratory (US)
Corresponding author
  • Ballouz, S.
  • Gillis, J.
Venue
Bioinformatics
Published
2015-02-28
Volume
31
Issue
13
Pages
2123-2130
ISSN
  • 1367-4803 (ISSN-L)
  • 1367-4811
OpenAlex
W2104724027
Cited by
215
References
47
Citations by year
2026: 7 · 2025: 15 · 2024: 7 · 2023: 21 · 2022: 15 · 2021: 31 · 2020: 18 · 2019: 27 · 2018: 24 · 2017: 23 · 2016: 20 · 2015: 6
FWCI
10.55
Type
journal article
Language
en
Open access
Locations
  • Bioinformatics (publishedVersion)
  • PubMed (publishedVersion)
  • Cold Spring Harbor Laboratory Institutional Repository (Cold Spring Harbor Laboratory) (acceptedVersion)
  • HighWire Press Open Archive (submittedVersion)
Topics
  • Life Sciences › Biochemistry, Genetics and Molecular Biology › Molecular Biology › Bioinformatics and Genomic Networks
  • Life Sciences › Biochemistry, Genetics and Molecular Biology › Molecular Biology › Gene expression and cancer classification
  • Life Sciences › Biochemistry, Genetics and Molecular Biology › Molecular Biology › Genomics and Phylogenetic Studies
Keywords
guilt by association, gene co-expression, network topology, hub genes, sample size requirements, sequencing depth, stochastic gene expression, microarray comparison, functional connectivity, gene function prediction
MeSH terms
Algorithms, Brain, Humans, Models, Theoretical, Sequence Analysis, RNA, Computational Biology, Gene Expression Profiling, Gene Regulatory Networks, High-Throughput Nucleotide Sequencing

About these checks

Registry, retraction, Cites and statistics results are computed, not judged, with one exception: a printed reference that no index lists is read once by a model before it counts as a citation error. Claims are extracted by a model and kept only when their quote appears verbatim in the text; each cited source is then checked, with a model’s help, for whether it says what the claim relies on. Those verdicts can be wrong — read the claim’s quote and the cited source before relying on one.

A language model drew the claims from the paper on 2026-10-06, under version 3 of the claim definition (model deepseek-v4.1-flash, prompt extract-v3).

A second model labelled each claim on 2026-10-06 (model jev-1.13-20260917, definition revision gold-guideline-v0.2).

Statistics and arithmetic are recomputed, not judged.

Confidence bands are shown only for fields calibrated on our annotated test set. None is calibrated yet, so no band is shown.

What counts as a claim ›How we measure confidence ›How we check this ›

Are you an author, or do you see a problem with this page? Request a review