Emergence and propagation of epistasis in metabolic networks

  1. Sergey Kryazhimskiy  Is a corresponding author
  1. University of California, San Diego, United States

Abstract

Epistasis is often used to probe functional relationships between genes, and it plays an important role in evolution. However, we lack theory to understand how functional relationships at the molecular level translate into epistasis at the level of whole-organism phenotypes, such as fitness. Here, I derive two rules for how epistasis between mutations with small effects propagates from lower- to higher-level phenotypes in a hierarchical metabolic network with first-order kinetics and how such epistasis depends on topology. Most importantly, weak epistasis at a lower level may be distorted as it propagates to higher levels. Computational analyses show that epistasis in more realistic models likely follows similar, albeit more complex, patterns. These results suggest that pairwise inter-gene epistasis should be common and it should generically depend on the genetic background and environment. Furthermore, the epistasis coefficients measured for high-level phenotypes may not be sufficient to fully infer the underlying functional relationships.

Data availability

All data generated or analyzed during this study are included in the manuscript and supporting files. Code is available on GitHub.

Article and author information

Author details

  1. Sergey Kryazhimskiy

    Division of Biological Sciences, University of California, San Diego, La Jolla, United States
    For correspondence
    skryazhimskiy@ucsd.edu
    Competing interests
    The authors declare that no competing interests exist.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0001-9128-8705

Funding

Burroughs Wellcome Fund (Career Award at Scientific Interface,1010719.01)

  • Sergey Kryazhimskiy

Alfred P. Sloan Foundation (FG-2017-9227)

  • Sergey Kryazhimskiy

Hellman Foundation (Hellman Fellowship)

  • Sergey Kryazhimskiy

National Institutes of Health (1R01GM137112)

  • Sergey Kryazhimskiy

The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.

Copyright

© 2021, Kryazhimskiy

This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.

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  1. Sergey Kryazhimskiy
(2021)
Emergence and propagation of epistasis in metabolic networks
eLife 10:e60200.
https://doi.org/10.7554/eLife.60200

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https://doi.org/10.7554/eLife.60200