Kazakh White-headed is the local beef cattle breed, which is bred in Central Asia countries. It was created in the beginning of 20 century by improving native Kazakh cattle by Hereford breed. The aim of our work was to characterize the genetic structure and to trace the presence of ancestral genetic components in the modern population of Kazakh White-headed cattle. The samples of modern representatives of Kazakh White-headed (KZWH_M, n=29) and Hereford (HRFD_M, n=25) breeds as well as historical specimens of native Kazakh breed (KZKH_H, n=2), dated by the first quarter of 20^th century, were subjected to the study. All works with historical specimen were performed in dedicated facility of the L.K. Ernst research Centre for Animal Husbandry. DNA from modern samples was extracted using DNA Extran 2 kit (JSC Syntol, Russia) and from historical specimen – using COrDIS Extract Decalcine kit (GORDIZ LLC, Russia). We genotyped 11 microsatellite loci (BM1818, BM2113, BM1824, ETH10, ETH225, INRA023, SPS115, TGLA53, TGLA122, TGLA126, and TGLA227). For historical samples the PCR reaction were carried out in five replicates to determine the consensus genotypes for each locus.

In total, we identified 82 microsatellite alleles. Five alleles, which were found in the historical specimens, were lost in the modern population of Kazakh White-headed cattle. We observed the highest level of genetic diversity (unbiased heterozygosity, allelic richness) in historical samples. The modern population of Kazakh White-headed cattle was closer to Hereford breed as was revealed by calculation of pairwise Nei and F_ST genetic distances. The STRUCTURE clustering confirmed the more similarity of genetic structure of modern Kazakh White-headed cattle with Herefords, but showed the visible presence the historical genetic components. The research results will be useful for developing the programs of conservation and sustainable use of Kazakh White-headed cattle.