Microsatellite-Based Insights into Bottleneck Dynamics in Awassi Sheep

Abstract

Awassi sheep is a strategically important indigenous breed in Türkiye, particularly valued for its dairy performance and environmental adaptability. In this study, 190 individuals sampled from flocks in the Gaziantep and Kilis provinces were genotyped using 17 microsatellite loci to characterize genetic variability and population structure. A total of 306 alleles were detected, indicating substantial allelic richness. The mean observed heterozygosity (Ho = 0.72) was lower than the expected heterozygosity (He = 0.82), suggesting low to moderate heterozygote deficiency potentially attributable to subpopulation structure (Wahlund effect). Genetic differentiation among flock subpopulations was low (FST = 0.019), indicating ongoing gene flow and weak population subdivision. Bayesian clustering analysis implemented in STRUCTURE identified three genetic clusters independent of strict geographic boundaries. Bottleneck analyses revealed no evidence of a recent reduction in effective population size (Ne). These findings indicate that genetic diversity has been effectively maintained and support the long-term sustainability of the selection scheme conducted under the “National Genetic Breeding Project in Small Ruminants under Breeders' Conditions” initiated in 2005.