1. Developmental Biology
  2. Evolutionary Biology
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Selection for increased tibia length in mice alters skull shape through parallel changes in developmental mechanisms

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Cite this article as: eLife 2021;10:e67612 doi: 10.7554/eLife.67612


Bones in the vertebrate cranial base and limb skeleton grow by endochondral ossification, under the control of growth plates. Mechanisms of endochondral ossification are conserved across growth plates, which increases covariation in size and shape among bones, and in turn may lead to correlated changes in skeletal traits not under direct selection. We used micro-CT and geometric morphometrics to characterize shape changes in the cranium of the Longshanks mouse, which was selectively bred for longer tibiae. We show that Longshanks skulls became longer, flatter, and narrower in a stepwise process. Moreover, we show that these morphological changes likely resulted from developmental changes in the growth plates of the Longshanks cranial base, mirroring changes observed in its tibia. Thus, indirect and non-adaptive morphological changes can occur due to developmental overlap among distant skeletal elements, with important implications for interpreting the evolutionary history of vertebrate skeletal form.

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All data generated or analysed during this study are included in the manuscript and supporting Source Data files.

Article and author information

Author details

  1. Colton Michael Unger

    Biological Sciences, University of Calgary, Calgary, Canada
    Competing interests
    The authors declare that no competing interests exist.
  2. Jay Devine

    Anatomy and Cell Biology, University of Calgary, Calgary, Canada
    Competing interests
    The authors declare that no competing interests exist.
  3. Benedikt Hallgrímsson

    Anatomy and Cell Biology, University of Calgary, Calgary, Canada
    Competing interests
    The authors declare that no competing interests exist.
  4. Campbell Rolian

    Comparative Biology and Experimental Medicine, University of Calgary, Calgary, Canada
    For correspondence
    Competing interests
    The authors declare that no competing interests exist.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0002-7242-342X


Natural Sciences and Engineering Research Council of Canada (Discovery Grant 4181932)

  • Campbell Rolian

University of Calgary (Faculty of Veterinary Medicine)

  • Campbell Rolian

Natural Sciences and Engineering Research Council of Canada (Canada Graduate Scholarship - Masters)

  • Colton Michael Unger

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


Animal experimentation: All animal procedures were approved by the Health Sciences Animal Care Committee at the University of Calgary (Protocols AC13-0077 and AC17-0026) and performed in accordance with best practices outlined by the Canadian Council on Animal Care.

Reviewing Editor

  1. George H Perry, Pennsylvania State University, United States

Publication history

  1. Received: February 18, 2021
  2. Accepted: April 23, 2021
  3. Accepted Manuscript published: April 26, 2021 (version 1)
  4. Version of Record published: May 13, 2021 (version 2)


© 2021, Unger et al.

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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