Domestication of dogs involved strong artificial selection. After their introduction into the human environment, dogs were exposed to factors that were not encountered in the wild. The skin and hair are barriers separating the organism from the environment, and melanin plays a significant role in their protective function. The study compared a fragment of the sequence of the DCT gene, which is involved in melanin synthesis, between two species: the dog, which is exposed to similar carcinogenic factors as humans, and the raccoon dog, a species related to the dog but less exposed to anthropogenic factors. A fragment of the DCT gene 443 base pairs in length was obtained. Two genotypes were distinguished within the raccoon dog population, differing in one nucleotide in the intron sequence (145A>G). Between the DNA profile of the dog and the consensus sequence of the raccoon dog, 18 polymorphic sites were found – 15 in the intron sequence and 3 in the exon sequence. One change in the exon (191G>A) caused an amino acid change (2E>K). The loss of two binding sites for factor SOX10 and one for JUN-FOS was noted in the dog sequence. On the basis of the sequence analysed, non-coding regions were found to be more susceptible to changes. Polymorphism in introns may affect the transcription profile of the DCT gene. The loss of binding sites for factors SOX10 and JUN-FOS in the dog may be an adaptive change to a different environment with respect to the raccoon dog.