The role of genetic indices in determining the race of the Arabian horses

Considering that the horse breeding industry is the fourth largest source of income generation in the world, and due to the diversity of species of horses in the world and the necessity of purity determination amongst breeders and horse owners, the importance of laboratory research in this regard is justified. According to past research, carried out sporadically in the country and abroad, there is a vacuum in the study of Iranian horses in terms of the diversity of genetic markers such as STR. The present study investigated short tandem repeat (STR) and allele frequency of 50 Arab horses using four loci (VHL20, AHT4, HTG4 and HMS7) recommended by the International Society for Animal Genetics (ISAG). For this purpose, genomic DNA was extracted from whole blood using the Miller procedure and amplified by Multiplex PCR with fluorescent primers.  The results indicated the presence of high genetic variability among the population of Arab horses. The number of alleles observed for each locus ranged from 6 to 9 with tAHT4 and VHL20 markers having the highest number of alleles with 9 alleles, and HTG4, with the highest heterozygosity. The HMS7 site had the lowest number of alleles among the sites examined with 7 alleles, and the VHL20 site had the lowest heterozygosity. The results of this study indicate a high frequency of genetic variation among the population of Arab horses.