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BMC ecology and evolution2021; 21(1); 178; doi: 10.1186/s12862-021-01907-5

Cranial shape diversification in horses: variation and covariation patterns under the impact of artificial selection.

Abstract: The potential of artificial selection to dramatically impact phenotypic diversity is well known. Large-scale morphological changes in domestic species, emerging over short timescales, offer an accelerated perspective on evolutionary processes. The domestic horse (Equus caballus) provides a striking example of rapid evolution, with major changes in morphology and size likely stemming from artificial selection. However, the microevolutionary mechanisms allowing to generate this variation in a short time interval remain little known. Here, we use 3D geometric morphometrics to quantify skull morphological diversity in the horse, and investigate modularity and integration patterns to understand how morphological associations contribute to cranial evolvability in this taxon. We find that changes in the magnitude of cranial integration contribute to the diversification of the skull morphology in horse breeds. Our results demonstrate that a conserved pattern of modularity does not constrain large-scale morphological variations in horses and that artificial selection has impacted mechanisms underlying phenotypic diversity to facilitate rapid shape changes. More broadly, this study demonstrates that studying microevolutionary processes in domestic species produces important insights into extant phenotypic diversity.
© 2021. The Author(s).
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Publication Date: 2021-09-21 PubMed ID: 34548035PubMed Central: PMC8456661DOI: 10.1186/s12862-021-01907-5Google Scholar: Lookup
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Summary

This research summary has been generated with artificial intelligence and may contain errors and omissions. Refer to the original study to confirm details provided. Submit correction.

This study investigates the diversification of cranial shapes in horses (Equus caballus) and the impact of artificial selection on it. Using 3D geometric morphometrics, researchers examined how morphological associations contribute to cranial ‘evolvability.’ It was found that changes in cranial integration contributed to the diversity of skull morphology and that artificial selection had a significant effect on the underlying mechanisms of phenotypic diversity.

Understanding the Study

  • The researchers used 3D geometric morphometrics, a technique that quantifies shape, to study the skull diversity of horses. This method captured the three-dimensional structure of horse skulls, offering a detailed representation of their morphology.
  • Their goal was to understand how morphological associations, or how different traits are connected, influence the horse skull’s evolvability. Evolvability refers to the capacity of a species to evolve, and in this context, it refers to the potential for skull shape to change over time.
  • They examined artificial selection’s impact, a process where humans intentionally breed animals to promote certain traits. In the case of horses, this could include both aesthetic preferences for particular skull shapes and practical demands for certain traits, such as size or strength.

Findings of the Study

  • The study found that changes in cranial integration, the level of coordination between different parts of the skull, contributed to the horse skull’s morphological diversity. This means that shifts in how different skull traits interact and influence each other have played a significant role in shaping horse skull diversity.
  • They found that artificial selection had a significant impact on the mechanisms underlying phenotypic diversity. This suggests that human breeding practices have actively shifted the traits of horse skulls, effectively driving their evolution in certain directions.
  • The researchers also found that a conserved pattern of modularity, the organization of traits into semi-independent units, did not limit large-scale morphological variations in horses. This could mean that even though some skull traits are interconnected, these connections don’t necessarily prevent significant changes in skull shape.
  • The study emphasizes that exploring microevolutionary processes in domestic species can offer valuable insights into existing phenotypic diversity, essentially contributing to our understanding of how species change over time and adapt to human influence.

Cite This Article

APA
Hanot P, Bayarsaikhan J, Guintard C, Haruda A, Mijiddorj E, Schafberg R, Taylor W. (2021). Cranial shape diversification in horses: variation and covariation patterns under the impact of artificial selection. BMC Ecol Evol, 21(1), 178. https://doi.org/10.1186/s12862-021-01907-5

Publication

BMC ecology and evolution
ISSN: 2730-7182
NlmUniqueID: 101775613
Country: England
Language: English
Volume: 21
Issue: 1
Pages: 178
PII: 178

Researcher Affiliations

Hanot, Pauline
  • Department of Archaeology, Max Planck Institute for the Science of Human History, Kahlaische Straße 10, 07745, Jena, Germany. hanot@shh.mpg.de.
Bayarsaikhan, Jamsranjav
  • Department of Archaeology, Max Planck Institute for the Science of Human History, Kahlaische Straße 10, 07745, Jena, Germany.
  • National Museum of Mongolia, 1 Juulchin Street, Ulaanbaatar, 15160, Mongolia.
Guintard, Claude
  • Unité d'Anatomie Comparée, Ecole Nationale Vétérinaire de l'Agroalimentaire et de l'Alimentation, Nantes Atlantique - ONIRIS, Route de Gachet, CS 40706, 44307, Nantes Cedex 03, France.
  • Groupe d'Etudes Remodelage osseux et bioMateriaux (GEROM), Unité INSERM 922 LHEA/IRIS-IBS, Université d'Angers, 4 rue Larrey CHU d'Angers, Angers, France.
Haruda, Ashleigh
  • Central Natural Science Collections (ZNS), Martin-Luther University Halle-Wittenberg, Domplatz 4, 06108, Halle (Saale), Germany.
  • School of Archaeology, University of Oxford, 1-2 South Parks Road, Oxford, OX1 3TG, UK.
Mijiddorj, Enkhbayar
  • Department of Archaeology, Ulaanbaatar State University, Luvsantseveen Street, 5th Khoroo, 15th Khoroolol, Bayanzurkh District, Ulaanbaatar, 13343, Mongolia.
Schafberg, Renate
  • Central Natural Science Collections (ZNS), Martin-Luther University Halle-Wittenberg, Domplatz 4, 06108, Halle (Saale), Germany.
Taylor, William
  • University of Colorado-Boulder, Museum of Natural History, Boulder, CO, USA.

MeSH Terms

  • Animals
  • Biological Evolution
  • Horses / genetics
  • Skull

Conflict of Interest Statement

The authors declare no competing interests.

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Citations

This article has been cited 4 times.
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