Allele pool of the DRB1 OLA gene in sheep of different breeds

The objective was to conduct a comprehensive analysis of the variability of the DRB1 locus OLA, to establish the level of polymorphism in the populations and breeds of sheep studied bred in different environmental conditions.

Material and methods included an assessment of the genetic differentiation of breeds from Russia (Dagestan Mountain, Dorper, Romanov, Suffolk) and one from the Republic of Kazakhstan (Akzhaik). The Romanov sheep populations were from farms in the Yaroslavl region and the Edilbaevskaya x Kalmyk crossbreeds were from Kalmykia (Russia). The decoding of the nucleotide sequence of DNA was carried out in 246 animals. Sequencing was carried out according to Sanger, followed by the use of bioinformatics analysis procedures. Statistical data processing was carried out using Microsoft Excel 2023, GenAlEx programs. The results showed that the between‐population variation (Frt = 0.008, p = 0.005) explained only 0.76 % of the variance, while the differences between the groups (Fsr = 0.044, p = 0.001) were 4.28 %. The negative Fis value (‐0.030, p = 0.997) indicated an excess of heterozygotes. The gene flow assessment (Nm = 4.58) confirmed a moderate level of migration. All the studied populations retained an excess of alleles with high levels of heterozygosity. A statistically significant level of population differentiation was noted (Fst = 5.2 %, p < 0.001).

The DRB1 OLA gene allele pool showed a typical structure with a predominance of individual variability in the sheep populations studied (95 %). Each breed contained alleles not found in others. Populations 3 and 9 were an exception owing to their small sample size (n ≤ 10), which limited the possibility of accurate statistical analysis and reliable identification of unique alleles.

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