Exploring genetic diversity and structural dynamics of genes influencing milk fatty acid composition in sheep breeds reared in Morocco.

Moroccan sheep breeds exhibit distinct adaptive traits shaped by diverse genetic ancestries and influenced by the country’s diverse environmental landscapes. In this work, we studied five breeds reared in different geographical regions of Morocco, namely Beni Guil, D’man, Sardi, Timahdite, and Ouled Djellal. We raegeted 105 high-confidence Single-Nucleotide Polymorphisms (SNPs) located within 18 genes associated with milk fatty acid profile in livestock, a trait of high nutritional and commercial impact. We assessed the genetic diversity and the structure and differentiation of the studied populations based on these SNPs. The D’man breed demonstrated the lowest genetic diversity and the highest inbreeding, while the Beni Guil breed exhibited the highest differentiation from the other breeds. The Discriminant Analysis of Principal Components we performed identified the 21 SNP variants that are responsible for the differentiation of the Beni Guil breed. Several of these breed-specific SNPs also showed deviations from the Hardy-Weinberg Equilibrium, possibly indicating long-term adaptation to the eastern Moroccan highlands. We used functional enrichment analysis on the genes containing the identified breed-specific SNPs. The most enriched biological processes were the cellular lipid metabolic process and fatty acid transport. We acknowledge that the small sample sizes for Beni Guil and Ouled Djellal might have affected the precision of allele frequency estimates and the strength of breed-specific conclusions. We considered these limitations during interpretation, and the results concerning these two breeds should be considered with caution until they are confirmed in larger sample sets.