POLYMORPHISM OF GH, CAST GENES IN DAGESTAN MOUNTAIN SHEEP, ANALYSIS OF THEIR GENOTYPES ASSOCIATIONS WITH INDICATORS OF IMMUNOBIOLOGICAL STATUS

Abstract

The real problem is the lack of any significant information about the gene pool of local, aboriginal breeds of cattle and small cattle, which are bred in various natural and geographical zones. In view of the fact that the peculiarity of their gene structures remains the reserve of genetic variability, due to which high adaptive qualities of populations are achieved, the main goal of this research work was to study the polymorphism of the GH and CAST genes of the Dagestan Mountain sheep and the participation of these polymorphisms in the formation of the immune status and reactivity. Genetic studies of the Dagestan mountain breed of sheep (for the CAST, GH genes) were carried out in the conditions of transhumance and livestock farms of Dagestan, the laboratory of genomic research, selection and breeding of the Federal State Budgetary Scientific Institution "FANC RD", an accredited laboratory of immunogenetics and DNA technologies of VNIIOK, a branch of the Federal State Budgetary Scientific Institution "Severo – Caucasian FNAC” by PCR-RFLP (polymyrase chain reaction - restriction fragment length polymorphism) using specific primers. As a result of PCR diagnostics, results were obtained showing a very low (0.03) frequency of the CASTN allele and a high (0.97) frequency of the CASTM allele of the CAST gene. The data obtained indicate a high – 93.0% frequency of occurrence of the homozygous CASTMM genotype, while the -CASTNN analogue was not found. The frequency of occurrence of the CASTМN genotype in this case had an indicator of 7.0%. Analysis of genotyping data indicates an ambiguous distribution of the allelic profile in the loci of the studied genes. The high frequency of occurrence (0.97) of the CASTM allele, but the low (0.03) of the CASTN allele led to a situation where the homozygous CASTNN genotype is absent in the studied sheep populations. This, in turn, could not but affect the values ??of the following constants: the degree of genetic variability (V, %), the number of effective alleles (Na), the levels of observed (Hobs) and theoretically expected (Hex) heterozygosity. According to the results of the comparative analysis of indicators that characterize immunity (immune reactivity index), we can conclude that the correct ratio of the number of T and B lymphocytes, their subpopulations - T-helpers and T-suppressors in blood lipids, CASTNN and GHBB genotypes provides a high immune response to external environmental conditions.