CHANGES IN THE FREQUENCY OF CALPASTATIN GENE ALLELES IN THE POPULATION OF PRYDNIPROVSKA MEAT BREED SHEEP

The paper reflects the study of changes in the frequency of alleles of the calpastatin (CAST) gene associated with meat productivity in sheep in the population of the Prydniprovska meat breed, which has been in a state of panmixic reproduction since 2020. DNA research on the polymorphism of the CAST gene in sheep was conducted previously in 2019 and repeated in 2024 using the PCR-RFLP method with the MspI restriction endonuclease. Our research was conducted on 47 Prydniprovska meat breed sheep (randomised sample from 2019) belonging to the Doslidne farm in the Poltava region, DNA typing revealed the following frequencies of CAST gene alleles: M–0.83 and N–0.17. Sheep breeding in the period 2020-2024 was carried out panmixically without the use of direct selection by genotype. The frequencies of CAST gene alleles were determined in 30 animals selected in 2024 by random sampling. The studies revealed a tendency towards an increase in the frequency of the N allele in the population compared to the previous period (M–0.75; N–0.25). A statistically significant difference in the genetic structure of the sheep population was established for the compared periods of its assessment (χ2 criterio n = 9.653, which significantly exceeds the critical level – 5.99 at p = 0.008). Over five years, the proportion of heterozygous MN animals increased significantly – from 12.8% to 43.3%, and the empirically determined population structure approached the theoretically calculated state of genetic equilibrium.