Investigating population structure and identifying signatures of selection in Iranian Kurdish and Arabian horses

The Arab horse breed is one of the most ancient horse breeds. Arabian horses are famous for endurance riding and flat racing. Moreover, this breed has contributed to the formation of some of the most important horse breeds in the world. Kurdish horses are found in rough terrain and hilly regions and they are suitable for riding in hilly areas and Polo tournament. To investigate the population structure and to find the signatures of selection in the genome of Arabian and Kurdish horses, blood and hair samples from 38 Arabian and 58 Kurdish horses were taken and genotyped using the 670K Axiom Equine Genotyping Array. Principal component analysis (PCA) was carried out on the genotypic data and Fst statistic for each SNP was calculated. Fst values were smoothed over each chromosome. PCA showed that the Arabian horse population is more genetically diverse than the Kurdish horses. We identified six genomic regions showing signatures of selection. The strongest signal of selection was found in ECA8. Annotation of the regions of the genome that showed selection signatures revealed candidate genese.g. CaMKK2, MLXIP and ATP2A2 that may involve in endurance riding and racing. These genes for further studies are proposed.