‘Wolf DNA’ Lurks in Many Modern Dog Breeds

At the whole genome level, dogs and wolves are clearly separated. However, when the research team constructed phylogenetic trees for each of the 1,582 genes, they found that no genes supported dog monophyly. Closer examination of mitochondrial DNA and Y chromosome phylogenetic trees revealed a complex interaction between canine and wolf lineages. This divergence reflects several cycles of gene transfer in the past.

Imprints on physique and personality

Researchers have found that wolf genes are linked to various dog traits, including size. Larger dogs tend to have more wolf ancestry, and certain working breeds, such as arctic sled dogs, wild dog breeds, and hounds, are more likely to possess this trait. Terriers, bird dogs and hounds, on the other hand, were least influenced by wolf genes.

Notably, among large service dogs, the influence of wolf ancestry varied significantly between breeds. The Sarabi dog, the Central Asian Shepherd Dog and the Anatolian Shepherd Dog, which are livestock guarding dogs of Turkey and Central Asia, inherited 0.5 to 1.2 percent of their genes from wolf ancestors, while Neapolitan Mastiffs, Bull Mastiffs and Saint Bernards showed almost no trace of wolf ancestry.

On the other hand, even the Chihuahua, the world’s smallest dog breed, has a low proportion of wolf ancestry, around 0.2 percent. These differences testify to the historical specificity of the evolution of the race.

Dog breed personalities also showed striking trends based on the proportion of wolf genes they possessed. Compared to breed-specific personalities described by the Kennel Club, the organization responsible for certifying dog breeds, breeds with fewer wolf genes were more likely to be described as “friendly,” “ready to obey,” “easy to train” and “affectionate.”

In contrast, breeds with strong wolf ancestry tended to be described as “wary of strangers,” “independent,” “wary,” and “territorial.” However, researchers cautioned that these descriptions are based on subjective human observations and it is unclear whether wolf DNA is directly related.

Adaptive genes that support survival

Wolf-derived genes are not just an evolutionary holdover, but may actually contribute to the survival of dogs. When Gene Ontology analysis was performed on regions of the village dog genome enriched in wolf ancestral elements, the only significant functional category was the olfactory transduction pathway. This result suggests that the influx of genes from wolves may have enhanced the village dog’s sense of smell, thereby improving its ability to seek out human food waste.

Village dogs that are not directly cared for by humans generally have a very low survival rate. For urban stray dogs, the survival rate at five months of age is less than 37 percent, with some reports suggesting it is as low as 16 percent. A keen sense of smell could play a key role in their survival in these harsh environments.