Dynamics of Structural Changes in the MSTN and MyoD1 Genes in Manych Merino Sheep

The paper presents changes in the structure of two genes, MSTN and MyoD1, whose functions are associated with the development of muscle tissue in animals. The aim of this study is to investigate changes in the structure of the MSTN and MyoD1 genes in the Manych Merino sheep population over ten years on the basis of the results of whole-genome sequencing of DNA samples. The object of the study in 2024 was Manych Merino rams. Sequencing was carried out using a NovaSeq 6000 genomic sequencer (Illumina, Inc., United States). The fragments obtained as a result of sequencing were mapped to the reference genome of Ovis aries assembly ARS-UI_Ramb_v2.0 (National Center for Biotechnology Information, NCBI. Genome. In the genes MSTN and MyoD1, 14 and 16 single nucleotide substitutions were identified, respectively. The results show that both genes have many variations, which can affect the phenotypic characteristics of sheep. General clustering showed that there are genotypes that were not detected in 2024, and a new genotype (B4) was also identified. The sources of genotypes B1, B2, and B3 are genotypes A1, A4, A6, A7, and A8. The frequency of mutant alleles in the MSTN and MyoD1 genes in sheep over the past ten years has shown some changes. In the substitutions rs119102828 and rs423466211 of the MSTN gene, the frequency of mutant alleles was 22% lower, and in the rs408710650 substitution, it was 8% less, compared to previous studies. In the MyoD1 gene, mutant alleles in the rs412308724 and rs403138072 substitutions were less common by 20 and 25%, respectively. In the rs416501217 substitution, the frequency of the mutant allele increased by 63% compared to previous studies. The detected changes in the frequency of mutant alleles and clustering of genotypes over the past ten years demonstrate the variability of genetic diversity. This emphasizes the need to continue monitoring genotypes to develop genetic certification programs and marker-associated selection.