Analysis of tail morphology and osteology in Ethiopian indigenous sheep

Amane, Agraw; Belay, Gurja; Kebede, Adebabay; Dessie, Tadelle; Worku, Setegn; Hanotte, Olivier; Vila, Emmanuelle

Abstract

Sheep adaptive diversity, including tail morphology, has been shaped by various factors, including natural and/or artificial selection for different traits. The Horn of Africa has historically been a major livestock entry point on the African continent from the Near Eastern centers of initial domestication. Ethiopia, in particular, possesses a marked sheep diversity, including the presence of breeds with four distinct tail morphotypes (short fat-tail, long fat-tail, fat-rump, and thin-tail) that do not co-exist elsewhere. The origin and development of the fat-tail, as well as the fat-rump, are still poorly known, and the osteological and metrical differences between the fat-tail morphotypes have never been studied. Here, we characterized the phenotypic diversity of Ethiopian sheep tails from morphological and osteological perspectives. Three tail measurements and 14 osteological traits were recorded in six breeds (Menz, Washera, Afar, Blackhead Somali, Bonga, and Gumz), representative of the four sheep tail morphotypes. Both linear discriminant and principal component analyses categorize the six sheep breeds into four distinct tail morphotypes. Analysis of variance of the morphological and osteological traits shows significant differences (P < 0.05) between the four tail morphotypes. The highest mean values of tail length, total caudal vertebrae length and the number of caudal vertebrae were recorded in the thin-tailed sheep, followed by the long fat-tailed sheep, whereas the lowest average values were recorded in the fat-rumped and short fat-tailed sheep. These traits are significantly and positively correlated with each other. Based on regression model analysis, it is possible to use tail length alone as a predictive tool to estimate the sheep tail osteology without killing the animal. Moreover, based on measurements of sheep caudal vertebrae, the osteologist can estimate other osteological traits and the tail length of that sheep, further differentiating its tail morphotypes. Significant differences (P < 0.05) were also observed in individual caudal vertebra length and breadth, tail breadth and tail circumference, and flat and concave-shaped caudal vertebrae between the short-tailed and long-tailed sheep. Our results provide important phenotypic baselines for genome diversity and adaptation studies and an osteological baseline for archeozoological work aiming to understand the history of sheep farming and breed development in past societies.

Citation

Amane, A., Belay, G., Kebede, A., Dessie, T., Worku, S., Hanotte, O., & Vila, E. (2023). Analysis of tail morphology and osteology in Ethiopian indigenous sheep. Journal of Archaeological Science: Reports, 47, Article 103776. https://doi.org/10.1016/j.jasrep.2022.103776

• Journal Article Type: Article
• Acceptance Date: Dec 1, 2022
• Online Publication Date: Jan 6, 2023
• Publication Date: 2023-02
• Deposit Date: Feb 4, 2023
• Publicly Available Date: Jan 7, 2024
• Journal: Journal of Archaeological Science: Reports
• Electronic ISSN: 2352-409X
• Publisher: Elsevier
• Peer Reviewed: Peer Reviewed
• Volume: 47
• Article Number: 103776
• DOI: https://doi.org/10.1016/j.jasrep.2022.103776
• Keywords: Archeology; Archeology
• Public URL: https://nottingham-repository.worktribe.com/output/16230587
• Publisher URL: https://www.sciencedirect.com/science/article/abs/pii/S2352409X22004394?via%3Dihub