Biodiversity of pigs of various breeds based on the analysis of mtDNA D-loop

Abstract

Mitochondrial DNA polymorphism, which is one of the most common genetic markers, is actively used in the study of various animal species. Since the mitochondrial genome has evolved over many years within a species, this has influenced the fixation of mutations and the formation of mitochondrial lineages that share a common origin and form mitochondrial genomes, called mtDNA haplogroups. The objectives of the work were to evaluate the genetic diversity of pigs of two maternal breeds of domestic reproduction based on the analysis of mtDNA D-loop polymorphism and to compare the results obtained with identical sequences from the NCBI database by breed and their geographic distribution. 39 Landrace pigs and 49 Large White pigs were used for the study. MtDNA was isolated from tissue samples (ear notch). The number of haplotypes, haplotypic and nucleotide diversity, and the average number of nucleotide substitutions per site were determined to assess the genetic diversity. 23 polymorphic sites were found: 21 in Landrace pigs, 17 in Large White pigs. A total of ten haplotypes were identified in the study population. The NCBI database found 75 identical sequences for pigs of different breeds bred around the world. After determining the nucleotide sequences of the D-loop fragment of the mtDNA of Landrace and Large White pigs of domestic reproduction and comparing them with the sequences from the NCBI database, the presence of identical sequences in the animals we studied and in the representatives of European and Asian breeds, including commercial and local was established. The materials obtained show that the assessment of mtDNA polymorphism contributes to the identification of phylogenetic relationships between populations, tracing of pedigree processes, and can be considered as an additional criterion of selection and breeding work.