Analysis of the mitochondrial haplogroups of farm and wild-living raccoon dogs in Poland.

Raccoon dogs' mitochondrial DNA genes (MT-CYTB, MT-CO1 and MT-CO2) containing a total of 1.5 kbp exhibited 11 synonymous substitutions in the polymorphism described, with almost 73% found in the gene MT-CO2. The polymorphism was observed in 27.3% of the loci in wild-living animals, and in over 90% of the loci in farm raccoon dogs. Seven mitochondrial haplogroups have been determined, among which three (Np1, Np2 and Np4) were found in the wild-living raccoon dogs and the other four (Np3, Np5, Np6 and Np7) in the farm animals. The occurrence of new haplogroups in the farm animals indicates the appearance of adaptive mutations. Differences were observed between the sequence under study and the reference sequence in MT-CYTB; they involved two non-synonymous substitutions (T304I and F332L). Analyses carried out to determine the deleterious effect of mutations indicated an almost 50% probability that a single amino acid substitution (T304I) in the protein has a negative impact on its function.