Would the Cephalic Development in the Purebred Arabian Horse and Its Crosses Indicate a Paedomorphic Process?
Abstract: This study examined paedomorphosis in PAH and F1 crossbreds. A sample of 99 horses was selected from 40 different breeders and consisted of three groups: stallions ( = 16), mares ( = 53), and geldings ( = 30), ranging from 10 months to 27 years in age. All horses presented a concave celloid lateral left head profile in the acquired photographic images. The hypothesis proposed in this study suggested the lateral profile of the head in juveniles was representational in the adult form due to the neonate's facial bones (part of the splanchnocranium) developing at a different rate to those of the skull. The methodology utilized geometric morphometrics to identify 23 landmarks so as to identify profile curvature indicative between the three groups (stallions, mares, and geldings). Principal component analysis reduced the number of variables to 14 examinable landmarks. Using a two-NPMANOVA and multivariate regression test, it was demonstrated that an isometric relationship between the concave celloid profile in the juvenile and its adult counterpart existed. This result supported the hypothesis that PAH and F1 crossbreds expressed a paedomorphic trait due to the adult form retaining the concave celloid profile identified in the juvenile.
Publication Date: 2022-11-16 PubMed ID: 36428393PubMed Central: PMC9686750DOI: 10.3390/ani12223168Google Scholar: Lookup
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Summary
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The research article investigates the concept of ‘paedomorphosis’ – the retention of juvenile traits into adulthood – in Purebred Arabian Horses (PAH) and their crossbreeds, and finds evidence for this phenomenon in the horses’ facial characteristics.
Research Goals
- The study aims to explore the concept of ‘paedomorphosis’ – a phenomenon where juvenile characteristics get retained into adulthood, particularly in Purebred Arabian Horses (PAH) and their F1 crossbred (first generation offspring).
- The researchers hypothesize that the head profile of juvenile horses is represented in their adult form, due to different rates of development in facial bones versus the skull.
- They seek to support this hypothesis by examining the lateral profile (side view) of the horses’ heads.
Methods
- A total of 99 horses from 40 breeders, ranging in age from 10 months to 27 years, were included in the study. This sample comprised stallions, mares, and geldings (neutered males).
- Photos were taken of the left side of each horse’s head, with all images showing a concave (inwardly curving) profile.
- A technique called ‘geometric morphometrics’ was used to identify 23 key points (or ‘landmarks’) on the horses’ facial profiles, and the data was reduced to 14 landmarks using a procedure called ‘principal component analysis’.
- Statistical tests (two-NPMANOVA and multivariate regression) were used to examine the relationships between the different points.
Results and Conclusions
- The study found an ‘isometric’ relationship – one where relative proportions are maintained – between the juvenile and adult head profiles.
- This result supports the researchers’ hypothesis and suggests that PAHs and their crossbreeds exhibit a paedomorphic trait because their adult form resembles the juvenile form.
- This work contributes to our understanding of horse breed development and can be potentially relevant for breeders and equine genomics researchers.
Cite This Article
APA
Salamanca-Carreño A, Parés-Casanova PM, Monroy-Ochoa NI, Vélez-Terranova M.
(2022).
Would the Cephalic Development in the Purebred Arabian Horse and Its Crosses Indicate a Paedomorphic Process?
Animals (Basel), 12(22), 3168.
https://doi.org/10.3390/ani12223168 Publication
Researcher Affiliations
- Facultad de Medicina Veterinaria y Zootecnia, Universidad Cooperativa de Colombia, Villavicencio 500001, Colombia.
- Generalitat de Cataluña, 25798 La Seu d'Urgell, Catalonia, Spain.
- Facultad de Medicina Veterinaria y Zootecnia, Universidad Cooperativa de Colombia, Villavicencio 500001, Colombia.
- Facultad de Ciencias Agropecuarias, Universidad Nacional de Colombia, Palmira 763531, Colombia.
Grant Funding
- ID2956 and ID3153 / Research Committee CONADI of the Cooperative University of Colombia
Conflict of Interest Statement
The authors declare that there are no conflict of interest.
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