In this study, we used mitochondrial (mt) DNA to reveal patterns of genetic diversity among six breeds of sheep native to Kazakhstan, including the Chu and Kalchengel types of Kazakh mutton-semifine-wool breed of sheep, Akzhayik, Edilbay, Kazakh fat-rumped semi-course-wool and South Kazakh Merino breeds. Mitochondrial DNA D-loop was studied in 64 samples to determine the genetic diversity of the local sheep breeds. The analysis identified 54 haplotypes and 113 polymorphic loci of mtDNA D-loop. For the studied breeds, haplotype diversity and nucleotide diversity were 0.993±0.005 and 0.039±0.001, respectively. The results indicated higher level of nucleotide diversity in the South Kazakh Merino (SKM) breed (0.047), while the lowest diversity was observed in the Edilbay breed (0.029). In addition, the average number of nucleotide differences (Kxy) and the average number of nucleotide substitutions (Dxy) were determined among the studied breeds. The minimal value of genetic distance was observed between Akzhayik mutton-wool and Kazakh fat-rumped semicourse-wool breeds (Kxy: 16.956 and Dxy: 0.039), while the maximum value was observed between the Edilbay and SKM breeds (Kxy: 24.600 and Dxy: 0.040). Phylogenetic analysis revealed the presence of three haplogroups, namely, A, B and C in the collected sample, while the haplogroups D and E were not found. The results indicated that 28 of 64 tested animals belong to haplogroup A (43.75%), whereas 25 of investigated animals were attributed to haplogroup B (39.06%) and 11 animals to haplogroup C (17.19%).

The article reflects the data of scientific research that can serve the practice of selection and breeding work under conditions of various forms of ownership, as well as the improvement of selection and breeding work and the technology of production of high-quality and competitive sheep products in the conditions of year-round use of the foothill-steppe and desert pastures of the south of Kazakhstan. The research of polymorphism systems of serum proteins of sheep's blood of different intra-breed types by gender and age groups revealed the presence of certain allele combinations and the ratio of transferrin and hemoglobin genotypes. It has been established that these animals have their own specific range of frequencies of occurrence of alleles and combinations of genotypes. Based on the results obtained, the possibility of using genetic blood markers in the early assessment of the productive qualities of animals has been established. As a result of scientifically based breeding methods, in the “Batai-Shu” LLP in Zhambyl region created a breeding australized herd of the South Kazakh Merino breed with a white wool yolk, a cut of washed wool of 3.1 kg with a yield of 48-50%.