USING THE GENETIC MARKER MC4R IN THE CREATION OF SPECIALIZED PIG LINES

The basis of effective development of modern pig-breeding is the creation of specialized lines and the use of hybridization to obtain heterosis crossbreds with high productivity. Marker-assisted selection is widely used in pig-breeding, allowing breeders to select animals at early ontogenetic stages using DNA analysis, thereby shortening the evaluation period and increasing the accuracy of breeding value prediction. One of the promising genetic markers for pig performance traits is the MC4R gene (melanocortin 4 receptor), whose polymorphic variants are associated with fattening and meat qualities. There are several approaches to selecting pigs for improved fattening and meat qualities using DNA markers and biochemical criteria. For example, M.E. Mikhailova et al. proposed a method for selecting pigs for improved meat and fattening qualities based on PCR-RLFP analysis of the IGF2 gene, selecting boars with Qq and QQ genotypes for mating with sows [1]. However, this method does not take into account the genotype of sows and relies on a different marker gene. In another approach patented by V.D. Kabanov, the selection of breeding young animals was carried out when the piglets reached a weight of 90-100 kg based on the concentration of free lysine in their muscle tissue [2]. Although this biochemical criterion reflects meat productivity, the need to grow the animals to a significant weight does not contribute to reducing the selection time. Another well-known method is aimed at selecting pairs of breeds, types, and lines based on the heterosis index, which is calculated based on genetic similarity in a number of immunogenetic loci. This approach allows for predicting the combinational ability of the original forms, but it is quite complex and time-consuming to implement in practice. The closest to our work is the method of diagnosing the breeding value of Duroc pigs based on the MC4R gene, which developed a test system for genotyping animals of this genotype [4]. The disadvantage of the prototype is that it does not take into account the purposeful formation of parental forms (lines) to obtain the effect of heterosis in the fattening and meat qualities of the offspring.