Genetic characteristics of local horse breeds by microsatellite DNA loci

Russia has a significant pedigree diversity of horse breeds with unique gene pools that are well adapted to a wide variety of harsh natural and climatic conditions, are characterized by universal performance and high productive qualities, and are of significant interest to the world horse breeding. Genetic studies of population diversity in horse breeding are very relevant, since many domestic horse breeds are under threat of extinction. Biomaterials (hair, blood, semen) from horses of 15 local breeds bred in the Russian Federation and neighboring countries (CIS) were selected for the research. The sample included 2,193 horses, including: Altaiskaya (n = 48), Bashkirskaya (n = 130), Buryatskaya (n = 30), Vyatskaya (n = 220), Zabaikalskaya (n = 34), Kyrgyzskaya (n = 100), Mezenskaya (n = 148), Mugalzharskaya (n = 109), Novoaltaiskaya (n = 514), Pechorskaya (n = 31), Shetland pony (n = 47), Priobskaya (n = 85), Tuvinskaya (n = 600), Khakasskaya (n = 47) and Yakutskaya (n = 50) breeds. The following indicators were used in the genetic and population analysis: the total number of allele variants (Na) in 17 microsatellite loci, the level of polymorphism (Ae), the average number of alleles per locus (Nv), observed (Ho) and expected (He) heterozygosity, coefficients of genetic similarity and genetic distances, as well as the coefficient of intrapopulation inbreeding (Fis). Modern local horse breeds, even relatively small in number, have a high level of biodiversity and a peculiar genetic structure, often with the presence of private alleles, which persists despite periodic crossing with stud breeds of different specializations. It was found that horses of local breeds possess a number of unique alleles, including ASB2T, HMS7S, HMS6J, HMS6H, HMS2T, HMS1O, HTG7L, HTG6L, HTG6H, VHL20S, ASB17Z, ASB17X, ASB17U, LEX3S, LEX3R and CA425E, which were not detected in representatives of stud breeds in the studied European populations. The majority of the studied breeds were characterized by a negative Fis value and the absence of inbreeding. The coefficients of genetic similarity of local breeds varied in a relatively wide range (0.828-0.973) and testified to the uniqueness of the gene pools of most local horse breeds of the Russian Federation, as well as confirmed the common origin of the Kyrgyzskaya horse with the horse populations of Southern Siberia.