On the origin of universal cell shape variability in a confluent epithelial monolayer

  1. Souvik Sadhukhan
  2. Saroj Nandi  Is a corresponding author
  1. Tata Institute of Fundamental Research, India


Cell shape is fundamental in biology. The average cell shape can influence crucial biological functions, such as cell fate and division orientation. But cell-to-cell shape variability is often regarded as noise. In contrast, recent works reveal that shape variability in diverse epithelial monolayers follows a nearly universal distribution. However, the origin and implications of this universality remain unclear. Here, assuming contractility and adhesion are crucial for cell shape, characterized via aspect ratio (r), we develop a mean-field analytical theory for shape variability. We find that all the system-specific details combine into a single parameter α that governs the probability distribution function (PDF) of r; this leads to a universal relation between the standard deviation and the average of r. The PDF for the scaled r is not strictly but nearly universal. In addition, we obtain the scaled area distribution, described by the parameter μ, α and μ together can distinguish the effects of changing physical conditions, such as maturation, on different system properties. We have verified the theory via simulations of two distinct models of epithelial monolayers and with existing experiments on diverse systems. We demonstrate that in a confluent monolayer, average shape determines both the shape variability and dynamics. Our results imply that cell shape distribution is inevitable, where a single parameter describes both statics and dynamics and provides a framework to analyze and compare diverse epithelial systems. In contrast to existing theories, our work shows that the universal properties are consequences of a mathematical property and should be valid in general, even in the fluid regime.

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We have uploaded the source files of the simulation data and the Mathematica analysis files in Dryad.

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Author details

  1. Souvik Sadhukhan

    TIFR Centre for Interdisciplinary Sciences, Tata Institute of Fundamental Research, Hyderabad, India
    Competing interests
    The authors declare that no competing interests exist.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0002-0926-6601
  2. Saroj Nandi

    TIFR Centre for Interdisciplinary Sciences, Tata Institute of Fundamental Research, Hyderabad, India
    For correspondence
    Competing interests
    The authors declare that no competing interests exist.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0003-0977-1947


Department of Atomic Energy, Government of India (RTI 4007)

  • Souvik Sadhukhan
  • Saroj Nandi

Science and Engineering Research Board (SRG/2021/002014)

  • Saroj Nandi

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

Reviewing Editor

  1. Karsten Kruse, University of Geneva, Switzerland

Publication history

  1. Preprint posted: August 21, 2021 (view preprint)
  2. Received: December 15, 2021
  3. Accepted: December 22, 2022
  4. Accepted Manuscript published: December 23, 2022 (version 1)
  5. Version of Record published: January 11, 2023 (version 2)


© 2022, Sadhukhan & Nandi

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. Souvik Sadhukhan
  2. Saroj Nandi
On the origin of universal cell shape variability in a confluent epithelial monolayer
eLife 11:e76406.

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