Identification of positive selection signatures in Iranian Kurdish and Arabian horses by linkage disequilibrium-based method

The Arab horses are famous for endurance riding, jumping and beauty. Kurdish horses are native to hilly regions of west of Iran and they are suitable for Polo tournament. Kurdish horses are shorter and heavier than Arabian horses. In this study, we use the linkage disequilibrium-based method, XP-EHH statistic, for Identification of regions that have undergone selection in the genome of Arabian and Kurdish horses. For this purpose, genomic DNA from blood and hair samples from 38 Arabian and 58 Kurdish horses were extracted. All DNA samples genotyped by the Axiom MNEC670 array. After data pruning, XP-EHH statistic was calculated. We identified 51 genomic regions (85 genes) in Iranian Arab horses and 7 genomic regions (13 genes) in Kurdish horses showing signatures of selection. We found positively selected genomic regions in the Iranian Arab horses associated with immune system related pathways, milk protein formation, muscle growth and development, vision, nervous system and body size whereas in the Kurdish horses associated with G protein–coupled receptors, growth and maturation of muscle fibers, cellular oxygen homeostasis and skin and hair pigmentation.