Association of single nucleotide polymorphisms in the somatotropin gene with indicators of meat productivity in meat-wool sheep

Abstract

Modern methods, which are based on the use of DNA technology, allow scientists to improve the accuracy and efficiency of traditional breeding by using molecular markers. One of the ways to identify markers is DNA assessment in the candidate gene, which is the basis of the trait and contributes to the manifestation of the phenotypic characteristics of the organism. Currently, there is growing interest in the genetic improvement of economically important traits in sheep [Fatima Abd Al-Muhsen et al., 2019]. The study of the relationship between gene polymorphism and productivity indicators has high practical importance, which lies in solving many applied problems of breeding. One of these tasks is to determine genetic markers which affect the meat productivity of sheep [Serdyuk G.N., Prituzhalova A.O., 2019; Pogodaev V.A., Kononova L.V., et al., 2019; Lushnikov V.P., Fetisova T.O., Selionova M.I. et al., 2020]. Growth hormone gene GH, which controls and regulates the growth and development of animals, can be considered as a promising marker gene for evaluating meat productivity. The study focuses on the research of the somatotropin gene polymorphism and the analysis of its associations with the indicators of meat productivity of meat-wool sheep of the genotype 1/2 Poll Dorset x 1/2 North Caucasian meat-wool (1/2 PD х 1/2 SC), which are bred in the Stavropol Territory. Polymorphism of somatotropin gene loci was carried out by polymerase chain reaction (PCR) followed by the determination of the restriction fragments lengths – RFLP. The results of PCR showed that the polymorphism of somatotropin gene is represented by two alleles A and B. When studying the polymorphism of GH gene in the experimental animals, genotypes AA, BB and AB were found with different frequency of occurrence. It was found that the heterozygous AB genotype (42.8%) was the most common in meat-wool sheep, while the homozygous AA and BB variants were basically equal and amounted to 29.7 and 27.5%. Further research made it possible to analyze the relationship of the allelic variants of the somatotropin gene with the slaughter parameters of meat-wool sheep. Based on the results, we found that the presence of heterozygous AB and homozygous BB genotypes has a positive effect on the indicators of sheep meat productivity.