Genomic scan for detection of selective sweeps in Turkmen horse population

Selection not only increases the frequency of new-useful mutations but also remains some signals throughout the genome. Since these areas are often control economically important traits, identifying and tracking these areas is the most important issue in the animal genetics. The aim of this study was to detecting signals of selection in the genome of Turkmen horse using 70K SNP chip. Twenty-three Turkmen horses selected from different areas of Gonbad-e kavuos, were Blood sampled. Then DNA extracted genotyped. To detect footprint of signal selection, some tests based on linkage disequilibrium (LD) such as extended haplotype homozygosity(EHH) and integrated haplotype Score (iHS) was used. First to identify regions of the genome that included the most signals of selection, iHS statistics was used and accordingly 6 genomic regions which were in the 99.99% percentile of iHS values selected for further analysis. These regions were located in 6 areas on chromosomes 4,5,7,8,9 and 10. Results of EHH test with bifurcation diagram of haplotype, confirmed signals of selection in these areas. Based on the results of the EHH test, sharp decay of LD in some regions was observed (chromosomes 7, 9 and 10) while in other regions it wasn’t so significant (chromosomes 4,5 and 8). As studied alleles on chromosomes 4,5 and 8 had long range of LD and had frequency of, respectively, %43, %52 and %37, these regions of the genome of Turkmen horse most likely has been the target of positive selection.