Analysis of genetic variation in different sheep breeds using microsatellites

Genetic variation in three Egyptian indigenous sheep breeds namely: Barki, Ossimi and Rahmani were investigated using fourteen microsatellite loci. The total number of alleles ranged from 6 in CSSM47 locus to 14 in TGLA 377 locus. The fourteen tested loci were all polymorphic in the three breeds. Major differences between the breeds were found at ten of the tested loci, where the alleles at the highest frequency are different in the three breeds. While, at loci OARCP20, OARVH72, CSSM47 and OARAE129, two of the tested breeds have similar alleles at the highest allele frequency. The average direct count of heterozygosity overall loci in each tested breed was less than the expected heterozygosity. Tests of genotype frequencies for deviation from the Hardy-Weinberg equilibrium (HWE), at each locus overall breeds, revealed significant departure from HWE due to heterozygote deficiency. A slightly high rate of inbreeding within the three breeds was noticed (global F-IS = 0.308). Low genetic differentiation was detected by estimation of F-ST index between all pairs of breeds. Cluster analysis revealed that Ossimi and Rahmani breeds clustered independently from Barki breed at 0.43 of genetic distance. The obtained results can be useful for the development of a rational breeding strategy for genetic improvement of sheep in Egypt.