Characterization of the morphometric diversity and ecogeographic population structure of local Algerian and Mauritanian goats

Background: Morphometric traits, defined as quantitative and qualitative measures of animal form and structure, are key indicators of goats’ adaptation to ecosystems. They also shed light on the interaction between genetics and the environment. Aim: This study characterizes the morphometric diversity of goats in four ecoregions: the local Arbia breed in 3 regions in Algeria and the Sahel breed in the Sahel region of Mauritania. Methods: Principal Component Analysis and Mahalanobis distances were used to reveal the phenotypic characteristics of 736 adult goats. Results: We identified three groups. Group 1, which includes desert and Sahelian regions, shows the highest divergence between goats (distance = 4.599), reflecting their contrasting adaptations: compact morphology in arid environments (HW = 65.1 cm, BL = 71.7 cm), and elongated necks in the Sahel (NL = 27.3 cm). Conversely, goats in the coastal and pastoral areas are morphologically closer (distance = 1.741), and form two distinct groups: group 2 includes robust goats (HW = 66.6 cm), typical of pastoral steppes, while goats in group 3 (coastal) have a deep chest (CD = 35.0 cm). These results suggest that ecological isolation is more likely to occur in extreme regions (desert/Sahel), whereas in temperate zones (coastal/pastoral), goat populations tend to be more homogeneous. Conclusions: The study advocates conservation strategies to improve goats’ water resilience in arid regions and optimize their productivity in pastoral areas. It also emphasizes the importance of integrating genomic data to further our understanding of the evolutionary mechanisms underlying the different adaptations.