THE USE OF MITOCHONDRIAL GENOME POLYMORPHISM TO ESTABLISH PRO-MATERNAL BREEDS IN THE FINAL HYBRIDS OF PIGS
Authors: Budakva Yelyzaveta , Pochernyaev Konstantin , Korinnyi Serhii , Povod Mykola 
Published: June 2022

DNA markers are a convenient tool for researching the origin of pig breeds. The characteristic feature of mitochondrial DNA is that mitochondria are transmitted only maternally to all their descendants. Knowing the peculiarity of the transmission of genetic information contained in the mitochondrial DNA, it becomes possible to establish the pro-maternal breeds of pigs of the final hybrid (Large White × Landrace) × Maxgro. Comparison of the maternal-inherited set of rectal fragments of pigs’ final hybrid of foreign selection (n=15) from the total sample (n=175) from RPE "Globinsky Pig Farm", Globyno, town Poltava region, Ukraine allowed getting reliable information of their origin. Laboratory research was carried out based at the Institute of Pig Breeding and Agricultural Production NAAS in the Laboratory of Genetics. As a genetic material, bristles from the auricle of pigs (Large White × Landrace) × Maxgro were used. Allocation was carried out according to Serhii Korinnyi methodology and other authors' publications in 2005 using Chelex -100 ion exchange resin. For the mitochondrial genome analysis, the method of polymorphism of the length of restriction fragments reinforced with amplified in PCR was used (Polymerase chain reaction-restriction fragment of polymorphism – PCR-RFLP). The site of the D-loop of the mitochondrial genome of a pig measuring 428 pairs of nucleotide (with Tas 1 recognition sites in positions 15558, 15580, 15616, 15714, 15758 p.n.) was analyzed. This method allows determining 18 haplotypes of the mitochondrial genome. With its use, mitochondrial haplotypes of pigs of the final hybrid were determined: 4 animals with haplotype C, 6 with haplotype N, and 5 with haplotype O. According to many authors pieces of research, these haplotypes characterize different breeds, namely C – Landrace, N – Large White (Asian type) and O – Landrace. The obtained data on the origin of animals of the final hybrid suggests that two-breed sows were the result of direct (Large White × Landrace) and recipient crossing (Landrace × Large White).It was established that mitochondrial genome polymorphism is an objective marker for determining the breed belonging of animals obtained even in complex hybridization schemes. In our opinion, at the initial stage of breeding work, it is important to establish associations of mitochondrial DNA haplotypes in animals of the final hybrid. Since mitochondria are transmitted along the maternal line only, 13 genes encoding the proteins of the respiratory chain, the identified haplotypes C, N, and O will serve as stable genetic markers. Having determined the correlations of phenotype signs of animals of the final hybrid and certain mitochondrial haplotypes, it is possible to purposefully lead the selection of maternal lines.Genetic examination in the establishment of maternal breeds of hybrid pigs with the help of markers of the mitochondrial genome and the search for a polymorphic area of the X and Y-chromosome to determine the ancestral line has become an urgent issue in continuing our research in modern pig breeding technologies of commercial lines. The work was done with the support of the National Academy of Agrarian Sciences of Ukraine 31.01.00.07. F. “Investigate the pleiotropic effect gens that the SNP use in marker-associated pig breeding”. DR № 0121U109838.