The relationships between chosen mitochondrial genes polymorphisms and performance traits in raccoon dogs were determined. The study involved 354 farmed raccoon dogs. Blood collected from the animals was the analysed biological material. Mitochondrial DNA genes, i.e. MT-CO1 (mitochondrially encoded cytochrome c oxidase I), MT-CO2 (mitochondrially encoded cytochrome c oxidase II), and MT-CYB (mitochondrially encoded cytochrome b) were amplified using the polymerase chain reaction method. The amplicons obtained were sequenced and subjected to bioinformatics analysis. Based on the nucleotide sequences, three haplotypes for the MT-CO1 gene fragment and two haplotypes for the MT-CO2 gene fragment were identified. The sequence of the MT-CYB gene was monomorphic. Based on the haplotypes, five previously undescribed mitochondrial haplogroups were determined. Statistical analysis revealed significant differences between the values of three of the five investigated performance traits of raccoon dogs and the identified haplotypes and mitochondrial haplogroups, taking into account predictors of direct additive effects, additive maternal effects, and fixed specific maternal environmental effects. The new mitochondrial haplogroups identified in the farmed raccoon dog population may imply constant emergence of adaptive mutations that are conserved in subsequent generations. The results of the association study indicate a statistically significant association between haplotypes and mitochondrial haplogroups of farmed raccoon dogs and their body weight, body size, and colour type, which allows considering MT-CO1 and MT-CO2 genes as candidate genes encoding these traits in raccoon dogs. The results of the molecular analyses can be applied to improve the performance traits in farmed raccoon dogs.

SummaryThe aim of the study was to assess the biodiversity of farmed fur animals from the Canidae family (common fox, polar fox, and raccoon dog) using nuclear and mitochondrial markers. The study involved 434 animals. The biological material included whole peripheral blood or skin tissue. The isolated genetic material was subjected to qualitative and quantitative analyses. Mitochondrial DNA (mtDNA) gene fragments (COX1, COX2, CYTB) and nuclear DNA (nDNA) gene fragments (MSTN1, MSTN2, MSTN3, IGF1, GHR) were amplified with the PCR (polymerase chain reaction) technique. The amplicons obtained were sequenced or subjected to PCR-RFLP (restriction fragment length polymorphism) reaction, and bioinformatics analyses were performed. The interspecific analysis of the nDNA sequences revealed a total of 25 polymorphisms. On the other hand, the interspecific analysis of the mtDNA gene fragments identified 277 polymorphisms. The COX1 gene fragment exhibited the greatest variability. It was shown that the frequency of polymorphisms within the mitochondrial genome was almost 20-fold higher than that in the nuclear genome of the raccoon dog. It was found that the genetic distances revealed by the analysis of the mitochondrial gene fragments were similar to the results obtained by the nDNA analysis. The genetic distance between the raccoon and common fox was the greatest. The smallest phylogenetic distance was revealed between the two fox species. The study results indicate mitochondrial and nuclear genes may be alternatively used for determining the phylogenetic relationships between fur animals from the Canidae family.

the aim of the study was to describe the mechanism of mitochondrial dna inheritance in a group of farmed raccoon dogs. the study involved 354 individuals. Whole peripheral blood was the research material. dna was isolated and Pcr was performed for two fragments of mitochondrial genes: coX1 (cytochrome oxidase subunit 1 gene) and coX2 (cytochrome oxidase subunit 2 gene). the Pcr products were sequenced and subjected to bioinformatics analyses. three mitochondrial haplotypes were identified in the coX1 gene fragment and two in the coX2 gene fragment. the analysis of mtDNA inheritance in the paternal line confirmed the three cases of paternal mtDNA inheritance, i.e. the so-called "paternal leakage" in the analysed population. in two families, all offspring inherited paternal mitochondrial dna, whereas in one family one descendant inherited paternal mtdna and another one inherited maternal mtdna. the lineage data indicated that one female which inherited maternal mitochondrial dna transferred it onto the next generation. To sum up, the results of the study for the first time demonstrated the phenomenon of "paternal leakage" in farmed raccoon dogs, which facilitated description of mitochondrial dna inheritance in the paternal line.