RESUMEN
From genetic point of view, differences between ancient and modern horses can be reconstructed by using the phylogeographic analysis of mitochondrial genomes and by studying phenotypically important nuclear loci. The variety of modern horse coat colors resulted from artificial selection indicates a high degree of domestication. We have conducted the phylogenetic analysis of mitochondrial DNA extracted from bone samples of six ancient horses from Tsaramburial in the Republic of Buryatia, and established that they belong to a haplogroup E by Achilli's classification. This haplogroup is found among modern horses of the Maremmano breed from Italy. Gray coat color different from wild type have been detected in two ancient horses, which demonstrates a sufficiently high domestication level of Buryat horses during the period I century BC to I century AD. The analysis of the mitochondrial genome hypervariable region fragments revealed that ancient Buryat horses belong to a haplotype X3 by Cieslak's classification, which is ancestral to the haplogroup X3 of modern horses in Mongolia, Tuva, and Buryatia.