Study of Genetic Structure and Accuracy of Assignment of Individuals to Five Horse Populations using Microsatellite Markers

In some cases, due to overlapping of morphological traits and parents incomplete recording information, it is difficult to determine the breed origin of a horse. The use of molecular methods for assigning individuals to their breed can be a significant help in this regard. The present study was conducted to investigate the genetic structure and the accuracy of the assignment of horses to the origin populations using microsatellite markers. For this purpose, samples from 165 horses including Caspian (35), Arabian (36), Turkoman (30), Thoroughbred (28) and Turkoman - Thoroughbred crossbred population (36) were randomly collected. Polymerase chain reaction was performed using 12 microsatellite markers recommended by the International Society for Animal Genetics (ISAG), and the PCR products were separated by 8% acryl amide gel and stained using silver nitrate staining procedure. Estimation of genetic parameters such as the number of effective alleles and the expected heterozygosity level showed a high genetic variation in the used markers. Among them AHT4 marker showed the highest (11.20 alleles) and the AHT5 showed the lowest (4. 28) effective alleles and AHT4 (0.82) showed the highest and ASB17 (0.67) showed the lowest genetic variation. The highest and lowest genetic distances were observed between Thoroughbred with Arabian and Caspian (0.91) and Thoroughbred with crossbred population (10.0). In conclusion, the markers used in this study, could correctly assign 79% of the individuals to their source populations. Therefore, in some cases microsatellite markers can be a helpful tool for determining the breed origin of the horse.