Genetic diversity within economically important loci in European, Middle Eastern, and African sheep breeds: An insight into their development

We could not observe the often described decline of heterozygosity with increasing distance to the domestication centre maybe because of high gene flow and gene introgression between breeds following domestication. Tendencies of clustering according to the local origin of the animals were visible, whereas a clear breed grouping was not identified. No significant difference was found by principal component analysis of casein haplotypes between dairy and non-dairy breeds. However, using Canonical Discriminant Analysis most of the non-dairy individuals were correctly assigned to the non-dairy group, with an increasing precision when considering both casein haplotypes and the remaining SNP. The distribution of variation in the production-related SNP analyzed reflects both the long history of migrations, adaption, isolation, and the most recent effect of gene flow or isolation due to selection in the different breeds.