DNA markers and microsatellite code (review)

The search for genetic markers that simplify the selection of animals for crosses, increasing the likelihood of offspring obtaining with the desired manifestation of economically valuable traits is a central problem in modern animal husbandry. Here, we discuss the most successful applications of various types of DNA markers of genomic element polymorphisms for solving specific breeding problems. Microsatellites are used to exclude errors of origin, single nucleotide polymorphisms (SNPs) to create maps of genomic regions in which polymorphism is associated with the variability of phenotypic characteristics (D.J. Rigden, X.M. Fernández, 2023) and to identify the localization of key genes of adaptation to natural selection factors at the natural habitat edges and in areas of animal husbandry risky (E.K. Cheruiyot et al., 2022; L. Buggiotti et al.., 2021, 2022). The loci of increased variability in the copyicity of genome regions (CNV) are used to assess their involvement in responses to natural and artificial selection factors of such polygenic systems as sensory, immune, and transporter (Y. Huang et al., 2021; P. Davoudi et al., 2022). The predominant involvement of regulatory networks including dispersed and tandem repeats, in particular microsatellite repeats, in epigenetic and phenotypic variability is discussed (R.P. Kumar et al., 2010). The structural and functional complexity of microsatellite loci, individual features of variability of specific loci and their participation in evolutionary, recombination, transcription processes are considered. Their involvement in the organization of secondary DNA structures, participation in the formation and variability of the architectonics of the interphase nucleus and regulation of gene expression profiles is noted (R.P. Kumar et al., 2010; X. Tang et al., 2022). The study of regulatory networks is of particular importance, since there is evidence that the size of the genome in animals of different taxa, as well as the distribution and composition of mobile genetic elements (sources of components of regulatory networks) differ significantly, in contrast to the similarity in the number of genes encoding proteins (V.I. Glazko et al., 2022). Accumulating evidence suggests that polylocus genotyping of individual microsatellites and dispersed repeats can contribute to solving practical problems, such as information on the specific features of the population-genetic structure, consolidation and differences between closely related groups of animals.