GENOME-WIDE ASSOCIATION STUDY AS A PROMISING METHOD IN THE LIVESTOCK BREEDING INDUSTRY (Review)

Abstract

The basis for efficient breeding of farm animals is the use of technologies based on the latest achievements in molecular genetics. Using marker-assisted selection methods, individuals are selected according to certain genes that regulate the formation of productive characteristics. As is known, a lot of economically important productivity characteristics are quantitative traits. Several genes may be responsible for their development and phenotypic manifestation at once. Among them, genes with a pronounced effect on the animal's phenotype were previously identified and used as DNA markers of productive characteristics. Meat productivity genes include myostatin (MSTN), callipyge (CLPG), calpain (CAPN1), calpastatin (CAST), growth hormone (GH). The genes prolactin (PRL), beta-lactoglobulin (BLG) are responsible for milk productivity, and keratin-associated protein 1.3 (KAP 1.3) is responsible for wool productivity. However, some of these genes are found only in one variant, usually positive, which was fixed as a result of selective breeding. Some other genes, for various reasons, for example, special climatic conditions or a diet, may not be so active in showing their characteristics. Therefore, it is especially important to search for new genes responsible for the implementation of a particular productive characteristic in farm animals. For this purpose, the livestock industry actively uses the technology of genome-wide association study, which identifies new candidate genes, which functions may be related to the phenotypic manifestation of the studied productivity parameter. Thanks to associative studies, new genetic markers and candidate genes for economically valuable traits in cattle, pigs and other animals were proposed. In this regard, the purpose of this review was to analyze modern research papers, which were devoted to the use of the method of genome-wide association study for the identification of new candidate genes for productive traits in various species of farm animals.