Cited by 455Bioinformatics and Genomic NetworksComplex Network Analysis TechniquesGraph theory and applications

Understanding network concepts in modules

Open access
Dong, Jun, Horvath, Steve·2007·BMC Systems Biology

Abstract

BACKGROUND: Network concepts are increasingly used in biology and genetics. For example, the clustering coefficient has been used to understand network architecture; the connectivity (also known as degree) has been used to screen for cancer targets; and the topological overlap matrix has been used to define modules and to annotate genes. Dozens of potentially useful network concepts are known from graph theory. RESULTS: Here we study network concepts in special types of networks, which we refer to as approximately factorizable networks. In these networks, the pairwise connection strength (adjacency) between 2 network nodes can be factored into node specific contributions, named node 'conformity'. The node conformity turns out to be highly related to the connectivity. To provide a formalism for relating network concepts to each other, we define three types of network concepts: fundamental-, conformity-based-, and approximate conformity-based concepts. Fundamental concepts include the standard definitions of connectivity, density, centralization, heterogeneity, clustering coefficient, and topological overlap. The approximate conformity-based analogs of fundamental network concepts have several theoretical advantages. First, they allow one to derive simple relationships between seemingly disparate networks concepts. For example, we derive simple relationships between the clustering coefficient, the heterogeneity, the density, the centralization, and the topological overlap. The second advantage of approximate conformity-based network concepts is that they allow one to show that fundamental network concepts can be approximated by simple functions of the connectivity in module networks. CONCLUSION: Using protein-protein interaction, gene co-expression, and simulated data, we show that a) many networks comprised of module nodes are approximately factorizable and b) in these types of networks, simple relationships exist between seemingly disparate network concepts. Our results are implemented in freely available R software code, which can be downloaded from the following webpage: http://www.genetics.ucla.edu/labs/horvath/ModuleConformity/ModuleNetworks.

The claims and statistics of this paper haven’t been checked yet.

Run the check — free, no account needed. It reads the open-access text and checks the sources it cites.

A few free checks a day · papers already verified open instantly · results are public

Integrity signals

Registry

Crossref · 10.1186/1752-0509-1-24

Cites

54 of 54 references verified0 citation errors · 0 not checkable

Statistics

Claims the paper makes

The claims and statistics of this paper haven’t been checked yet.

Run the check — free, no account needed. It reads the open-access text and checks the sources it cites.

A few free checks a day · papers already verified open instantly · results are public

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?

  • Hierarchical clustering on the network structure allows uncovering functional modules of genes whose expression profiles are tightly intertwined, which typically correspond to specific biological processes and disease states.

    “Hierarchical clustering on the network structure allows us to uncover functional modules of genes whose expression profiles are tightly intertwined,3,4 which typically correspond to specific biological processes and disease states.”

    From hdWGCNA identifies co-expression networks in high-dimensional transcriptomics data (2023) · cites this paper as [4]

    The Background section describes defining modules as branches of a hierarchical-clustering dendrogram, and the Results section applies this method to gene co-expression networks. The Results also report that most modules are enriched for known gene ontologies, supporting a link to biological functions. The paper does not establish that these modules typically correspond to disease states. (LLM, conf=0.87)

    Experimental — accuracy not yet measured

Self-check

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

The self-check needs the paper’s full text.

Cites

Flagged first, then by citations

Cited by

Sorted by citations

Authors
Dong, J., & Horvath, S.
Affiliations
University of California, Los Angeles (US)
Corresponding author
Horvath, Steve
Venue
BMC Systems Biology
Published
2007-06-04
Volume
1
Issue
1
Pages
24-24
ISSN
1752-0509 (ISSN-L)
OpenAlex
W2057498577
Cited by
455
References
54
Citations by year
2026: 2 · 2025: 22 · 2024: 14 · 2023: 19 · 2022: 29 · 2021: 37 · 2020: 26 · 2019: 28 · 2018: 23 · 2017: 33 · 2016: 18 · 2015: 33 · 2014: 34 · 2013: 38 · 2012: 30
FWCI
5.57
Type
journal article
Language
en
Open access
Locations
  • BMC Systems Biology (publishedVersion, cc-by)
  • Europe PMC (PubMed Central) (publishedVersion, cc-by)
  • PubMed Central (publishedVersion, cc-by)
  • PubMed (publishedVersion)
Funders
  • National Institutes of Health (1u24ns043562-01)
  • National Institute of Mental Health
  • National Institute of Allergy and Infectious Diseases (U19AI063603)
  • National Institute of Neurological Disorders and Stroke (1U24NS043562-01)
Topics
  • Life Sciences › Biochemistry, Genetics and Molecular Biology › Molecular Biology › Bioinformatics and Genomic Networks
  • Physical Sciences › Physics and Astronomy › Statistical and Nonlinear Physics › Complex Network Analysis Techniques
  • Physical Sciences › Mathematics › Geometry and Topology › Graph theory and applications
Keywords
network concept, module networks, connectivity, clustering coefficient, network heterogeneity, network density, centralization, gene co-expression network, protein-protein interaction network, network module detection
MeSH terms
Animals, Computer Simulation, Drosophila, Models, Biological, Terminology as Topic, Proteins, Yeasts, Gene Expression, Cluster Analysis, Gene Regulatory Networks, Metabolic Networks and Pathways

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.

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