Thesis deals with the research results of Ukrainian gray breed genetic structure according to QTL-markers: CSN3 kappa-casein gene, BLG (beta-lactoglobulin gene), GH (gene of growth hormone), TG5 (gene of thyroglobulin), CAPN1 530 (сalpayn gene) and BoLA-DRB3 gene.
It was identified that allele В was the most frequent (76,6%) according to BLG gene that led to the predominance of homozygous genotype ВВ (56,1%). Homozygous genotype АА was found only in 2,9% of animals.
According to the CSN3 gene, most of animals (46,2%) are carriers of the heterozygous genotype AB. The genotypes of BB and AA were determined, respectively, with a frequency of 13,9% and 39,9%. Allele A prevails in the breed (63%). According to the complex genotypes of protein exchange genes, such genotypes dominate CSN3АВ/βLGВВ (31,8%), CSN3АА/βLGВВ (19,7%) and CSN3АВ/βLGАВ (17,3%).
According to the GH gene, the absence of animals with genotype VV was defined. Significant prevalence of the L allele (95.7%) resulted in the dominance of the genotype LL (91,3%).
According to the TG5 gene, TT and SS homozygous genotypes were determined, appropriately, in 11,6% and 33,5% of the tested animals. The allele C was more common (61%).
According to the CAPN1 530 gene, a significant prevalence of the homozygous genotype GG (84,4%) was revealed, whereas the AA genotype was found only in 0,6% of the researched animals. The dominant allele G appeared in 91,9% of cows. According to the complex genotypes of lipid metabolism genes such genotypes as GHLL/TG5CT/CAPN1GG (42,8%), GHLL/TG5CC/CAPN1GG (26,0%) and GHLL/TGТT/CAPN1GG (9,2%) prevail.
The study of the allele polymorphism for the BoLA-DRB3 gene identified the presence of 27 alleles out of 54 Van Eijk described and 6 "non-established nomenclature" alleles: *jab, *jba, *jbb, *nad, *nda and *had, the total frequency of which was 7,14%. With a frequency of more than 5%, three alleles BoLA-DRB3.2*16, *12 and *06 were found. The allele BoLA-DRB3.2*16 showed the maximum (44,2%) in the breed. 50 genotypes were identified, with the most frequent *16/*16 (19,6%), *12/*16 (11,6%), *06/*16 (7,14%) and *16/*24 ( 5,36%).
The frequency of genotypes based on the genes GH, βLG, CSN3, TG5 and CAPN130 in the descendants of Ukrainian gray breed bulls was established. By the BoLA-DRB3 gene, the most common breed *16 allele is predominant in the allelepool of all bulls descendants. Its share among the descendants of the breed Trubach 0071/145 was 40%, Drakon 1780 – 47,9%, Milan 0066/137 - 50% and Gudka 3001/547 – 43,4%. This figure amounted to 43,5% for the descendants of Shamrina line.
