Two mitochondrial genes are associated with performance traits in farmed raccoon dogs (Nyctereutes procyonoides)

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.