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The formation and functioning of the animal reproductive system occurs as a result of the coordinated interaction of a wide range of genes. To search for causal mutations, work was carried out to search for polymorphic variants in the marker regions detected using GWAS. The four single-nucleotide substitutions in the exon of the GRM8 gene identified during the studies and the association of these SNPs with sperm quality was carried out. Semen from 22 stallions was collected. Sperm volume, concentration and progressive motility were assessed. Sequencing of the sections of the candidate GRM8 gene was carried out using an Applied Biosystems 3500 genetic analyzer. For the rs1138419111 genotype, no significant differences were found in the studied parameters. According to the identified single nucleotide substitution rs1147388106, the highest ejaculate volume was in stallions with the GG genotype (55.9±26.5 ml) compared to stallions with the GA genotypes (32.5±13.9 ml) and AA (18.0±33,6) (p < 0.05). When analyzing data on SNP rs395286150, stallions with a heterozygous CT genotype had the best sperm quality. Thus, the cell concentration was 317.0±66.5 million/ml in stallions with the CT genotype, 209.6±58.2 and 189.5±74.9 % with the CC and TT genotypes, respectively (P < 0.05). The progressive sperm motility of stallions with the CT genotype was 65.5±20.5% versus 48.7±22.0% in stallions with the TT genotype and 48.4±18.6% with CC. Analysis of data on SNP rs394524550 revealed a significant effect of the genotype on progressive motility. Stallions with the AG genotype had a progressive motility of 64.6±16.3%, and those with GG and AA 32.7±15.7 and 49.6±18.1%, respectively (P < 0.05). Thus, as a result four single nucleotide polymorphisms were identified in the exon of the GRM gene. Three of them were significantly associated with such indicators of sperm quality as ejaculate volume, concentration and progressive motility. Project No. 0445-2021-0011. [ABSTRACT FROM AUTHOR]

Reindeer are one of the main representatives of the ecosystem of the Arctic zone and the only possible object of economic activity of the indigenous peoples of the polar regions of Russia. Reindeer meat is a valuable source of complete protein in the diet of the Evenks, Nenets, Yakuts and other peoples of the Far North. Four breeds of reindeer have been bred in Russia - Nenets, Evenk, Chukchi and Even. Evenk and Nenets are the most numerous. They live in different climatic zones and differ significantly in phenotypic characteristics (size and body weight). Populations of wild reindeer are also widespread. The problem of increasing the meat productivity of the main breeds of domesticated reindeer can be solved by searching for casual polymorphisms in candidate genes responsible for the growth and development of muscle tissue. Thus, polymorphism of the LCORL gene (mRNA liganddependent nuclear receptor of the corepressor type, which is a transcription factor) is associated with body weight and size in many mammals. We sequenced exon 7 of the LCORL gene and found seven SNPs, six of which are nonsynonymous and lead to a change in the amino acid composition of the protein. There was a significant difference in the occurrence of wild and mutant alleles in the three analyzed populations (wild reindeer, Nenets breed, Evenk breed), which indicates the presence of selection pressure on the L?ORL gene region, and also indirectly confirms the significance of the polymorphism of this locus for phenotypic variability in height and size of the reindeer. Studies of associations of LCORL gene polymorphisms on live weight and growth in other animal species suggest that some of the found SNPs may be true causal quantitative trait loci (QTL) in domestic reindeer breeds. Project No. 0045-2021-0010. [ABSTRACT FROM AUTHOR]

Genetic resistance to sperm cryopreservation is an important factor in the sires selection. In our study, we studied the cryoresistance of the sperm in Gallus gallus, Bos taurus, Equus ferus caballus. Sperm quality was assessed using computer-assisted semen analysis (CASA). Genetic studies were performed using Affymetrix Axiom®600k Array chips for cocks, Affymetrix Axiom®600k Array for stallions and BovineSNP50 for bulls. For the analysis of genotypes, the GWAS (Genome-Wide Association Studies) was used. The calculations were carried out using the PLINK and EMMAX programs. The candidate genes found as a result of our work were compared with the functions of orthologous genes, according to the publications of other researchers. As a result of comparing different animal species, a common candidate gene was found, localized on chromosome 3 (Gallus gallus) and on BTA9 (Bos taurus) BCKDHB gene encodes the beta subunit E1 of branched chain keto acid dehydrogenase, which is a multienzyme complex associated with the inner membrane of mitochondria. In roosters, it was associated with the preservation of sperm motility after cryopreservation, and it was found in the analysis of the integrity of the sperm head in bulls. The functioning of genes associated with meiosis and sperm maturation is an important condition for maintaining its quality after freezing. The work of genes responsible for the formation of membranes and various cellular structures associated with the functions of spermatozoa is also an important factor in cryoresistance. Another important condition for the functioning of the sperm is the expression of genes that prepare the sperm for fertilization. These are calcium metabolism genes involved in preparation for capacitation. Changes in the structure of proteins can lead to premature capacitation and disruption of sperm integrity. The found molecular genetic markers will be used to select sires whose sperm are suitable for freezing. Project of RSF № 18-16-00071. [ABSTRACT FROM AUTHOR]