Genomic study of population structure and linkage disequilibrium in some Iranian indigenous sheep breeds

Genomic technologies, such as high-throughput genotyping based on SNP arrays, have great potential to decipher the genetic architecture of complex traits and provide background information concerning genome structure in domestic animals, including the extent of linkage disequilibrium (LD). In this study, Illumina OvineSNP50 BeadChip array was used to estimate and compare LD, effective population size (Ne) and heterozygosity in three Iranian sheep populations consisting Afshari (N=41), Moghani (N=35) and Qezel (N=35) breeds. The average LD (measured by r2) estimated for all pairwise combinations of SNPs with average distance 58, 56 and 56 Kb were 0.151 ± 0.207 for Afshari, 0.131± 0.190 for Moghani and 0.121 ± 0.148 for Qezel breeds, respectively. The highest averages of r2 on autosomes were obtained for chromosome 2 in Afshari and Qezel and chromosome 12 in Moghani breeds. The Qezel breed showed highest genetic diversity based on effective population size and heterozygosity, whereas the lowest value was found in Afshari breed. Due to low LD values estimated in this study, the results showed to achieve the genomic prediction accuracy of 85% in genomic selection and association studies, the density of marker must be higher than 50K SNPChip.