Microsatellite Analysis of Genetic Diversity and Population Structure of the Arabian Horse Breeds

The Arabian horse breed is one of the oldest and most influential breeds throughout the world. There have been few quite studies of genetic diversity in this breed; all of them were about the modern Arabian populations. In this study, old and modern Arabian populations were represented by (682) horses, including Syrian, Saudi, Persian, Shagya, Polish Arabian, Akhal Teke, Turkoman, and Caspian population. Analysis of genetic structure of these populations was tested using 15 Microsatellite markers. Standard diversity indices, deviation from Hardy-Weinberg, the inbreeding level, AMOVA and tests for genetic bottlenecks were applied in this study. In addition to three different models of genetic distances, the genetic relationships among populations were analyzed by the factorial correspondence analysis and all samples were assigned into clusters using the Bayesian method.

 The number of alleles per locus varied between 2.8 to 5.6 and 5.1 to 8.5 in modern and old populations, respectively, while observed heterozygosity varied between 0.39 to 0.69 and 0.68 to 0.72 in modern and old populations, respectively. The results show a higher level of diversity within the old populations such as Syrian populations. In contrast, the modern populations have lower values of diversity.  Analysis of molecular variance detected 79% of variance within populations and 21% between populations. Further results will give more details about the relationships among those populations.  Such study will give an integrative description of the current status of the genetic diversity for Arabian horse populations and facilitate the development of conservation programs for this highly important breed.