ASSOCIATION OF THE CAPN1 GENE POLYMORPHIC VARIANTS WITH LIVE WEIGHT IN THE KALMYK FAT- TAILED SHEEP AND THEIR CROSSES WITH CHAROLAIS AND DORPER BREEDS

The purpose of research is to study the phenotypic effect of genotypes of the polymorphic calpain gene (CAPN1) on live weight in Kalmyk fat-tailed sheep and their crosses with the Charolais and Dorper breeds to substantiate the possibility of genetic marking of productivity at an early age. Objectives – carrying out genotyping and accounting of productivity indicators of animals of the Kalmyk fat-tailed breed (KK), Charolais (Sh), Dorper-Kalmyk crossbred ewes (½D×½KK), obtained purebred and crossbred young animals; establishing the influence of genotypes for the CAPN1 gene on live weight and average daily gain. It was found that in Kalmyk fat-tailed and Charolais breeding rams, carriers of the C allele in the CAPN1 gene were more often detected, while among purebred and crossbred ewes the occurrence of the C and T alleles was equal. In purebred young animals and ½ Sh ×½KK crosses, individuals with the T allele predominated; in ½ Sh ×¼D×¼KK crossbreeds, the carriers of the C allele predominated. Population genetic analysis in none of the groups did not reveal significant differences in the observed genotype frequencies from those theoretically expected at Hardy-Weinberg equilibrium. Regardless of breed and sex, the live weight of young animals at birth of different genotypes for the CAPN1 gene was similar, while at four months of age, both rams and lambs with the CC genotype had a significant superiority over their peers of other genotypes. In purebred rams, the greatest difference was observed between animals of the CC and ST genotypes, in crossbreeds ½ Sh ×½KK – animals of the CC and TT genotypes, which amounted to 10.4 and 8.1 %; 9.94 and 10.95 % (p < 0.05), respectively. Among the females, the greatest differences were observed during purebred breeding between animals of the CC and TT genotypes – 15.6 and 16.6 % (p < 0.05), respectively.