Polymorphism of the insulin-like growth factor-1 gene and its association with signs of sheep dairy productivity

The study of polymorphism of productive marker genes has significant potential for improving dairy sheep breeds in the Russian Federation. The introduction of genomic breeding methods based on identified markers will make it possible to purposefully increase the milk productivity of different animal breeds. The purpose of this study was to study the polymorphism of the insulin-like growth factor-1 (IGF-1) gene and to identify the association of polymorphic variants of the gene with indicators of dairy productivity in Lacon sheep. The object of the study is sheep of the Lakon breed (n = 39), bred on the farm of IP “Wanzha” Belogorsky district of the Republic of Crimea. Allelic variants of the IGF-1 gene were identified using PCR-RDRF analysis, which made it possible to differentiate genotypes based on the polymorphism of the nucleotide sequence at the restriction site. Genotyping of Lacon sheep showed that this sample is polymorphic for this gene, that is, the presence of two alleles (C and T) and three genotypes with a predominance of the heterozygous CT variant (89.7%) was noted. Individuals with the CT genotype demonstrated significantly higher fat (6.83%) and protein (5.24%) content in milk compared to TT homozygotes. The data obtained may indicate the potential value of the C allele as a marker for breeding to improve milk quality. The prospects of the work include the validation of the identified association in an expanded sample and the study of the relationship of the polymorphism of the insulin-like growth factor-1 gene with other economically useful traits.

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