Morphological integration in the appendicular skeleton of two domestic taxa: the horse and donkey.
Abstract: Organisms are organized into suites of anatomical structures that typically covary when developmentally or functionally related, and this morphological integration plays a determinant role in evolutionary processes. Artificial selection on domestic species causes strong morphological changes over short time spans, frequently resulting in a wide and exaggerated phenotypic diversity. This raises the question of whether integration constrains the morphological diversification of domestic species and how natural and artificial selection may impact integration patterns. Here, we study the morphological integration in the appendicular skeleton of domestic horses and donkeys, using three-dimensional geometric morphometrics on 75 skeletons. Our results indicate that a strong integration is inherited from developmental mechanisms which interact with functional factors. This strong integration reveals a specialization in the locomotion of domestic equids, partly for running abilities. We show that the integration is stronger in horses than in donkeys, probably because of a greater degree of specialization and predictability of their locomotion. Thus, the constraints imposed by integration are weak enough to allow important morphological changes and the phenotypic diversification of domestic species.
© 2017 The Author(s).
Publication Date: 2017-10-06 PubMed ID: 28978726PubMed Central: PMC5647294DOI: 10.1098/rspb.2017.1241Google Scholar: Lookup
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Summary
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This research is about studying the correlation between the structures of the skeletal system in horses and donkeys and how this relationship is influenced by both natural and artificial selection. The analysis, conducted on 75 horse and donkey skeletons, suggests that morphological integration, which is the developmental connection between different body parts, showed a higher degree of connection in horses when compared to donkeys. This, researchers believe, might be due to the higher degree of specialisation in the locomotion of horses.
Explaining the Concept of Morphological Integration
- Morphological integration is the biological concept that explains the connection or dependency between different parts or features of an organism’s body. This study looks at such connections in the appendicular (limbs) skeleton of domestic horses and donkeys.
- If two or more parts of an organism’s body exhibit co-variance (change together), they are said to be morphologically integrated. This concept is crucial in understanding the development, functionality, and evolution of organisms. For instance, a bird’s wing size and shape might be linked to the size of its tail feathers for balance during flight. Changing one aspect, under natural or artificial selection, might thus affect the other.
How Were the Studies Conducted?
- Three-dimensional geometric morphometric studies were carried out on 75 horse and donkey skeletons in order to figure out how distinct the integration patterns were in these animals.
- Geometric morphometrics is a method used in studying the shape and size differences and correlations between different structures of an organism’s body, using statistical analysis and measurements.
What Was Found?
- Results from the study indicate that horses have a higher integration or correlation between different parts of their appendicular skeletons than donkeys.
- One reason for this, the researchers speculate, could be the degree of movement specialization in horses. In other words, the horse’s skeletal structure may be more adapted for particular types of movement, like running, than that of donkeys’.
What Does This Mean for Evolution & Selection?
- The findings of the study suggest that the constraints imposed by morphological integration are weak enough to allow significant morphological changes and the phenotypic diversification of domestic species.
- This points towards the fact that in spite of the high degree of morphological integration in horses, the influence of both natural and artificial selection can bring about significant changes in the body structure of these animals.
Cite This Article
APA
Hanot P, Herrel A, Guintard C, Cornette R.
(2017).
Morphological integration in the appendicular skeleton of two domestic taxa: the horse and donkey.
Proc Biol Sci, 284(1864), 20171241.
https://doi.org/10.1098/rspb.2017.1241 Publication
Researcher Affiliations
- UMR 7209 « Archéozoologie et Archéobotanique: sociétés, Pratiques et Environnements » (CNRS, MNHN), Muséum national d'Histoire naturelle, Sorbonne Universités, 55 rue Buffon CP 56, 75005 Paris, France pauline.hanot@mnhn.fr.
- UMR 7179 « Mécanismes Adaptatifs et Évolution » (CNRS, MNHN), Muséum national d'Histoire naturelle, Sorbonne Universités, 57 rue Cuvier CP 55, 75005 Paris, France.
- École Nationale Vétérinaire, de l'Agroalimentaire et de l'Alimentation, Nantes Atlantique-ONIRIS, route de Gachet, CS 40706, 44307 Nantes Cedex 03, France.
- UMR 7205 « Institut de Systématique, Évolution, Biodiversité » (CNRS, MNHN, UPMC, EPHE), Muséum national d'Histoire naturelle, Sorbonne Universités, 45 rue Buffon, 75005 Paris, France.
MeSH Terms
- Animals
- Biological Evolution
- Bone and Bones / anatomy & histology
- Breeding
- Equidae / anatomy & histology
- Female
- Forelimb / anatomy & histology
- Hindlimb / anatomy & histology
- Horses / anatomy & histology
- Locomotion
- Male
- Selection, Genetic
Conflict of Interest Statement
The authors declare no competing interests.
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