‘Wolf DNA’ Lurks in Many Modern Dog Breeds

At the whole genome level, canines and wolves are clearly separated. However, when the research team constructed phylogenetic trees for each of the 1,582 genes, they found that not a single gene supported the monophyly of dogs. Further examination of the mitochondrial DNA and Y-chromosome phylogenetic trees revealed a complex interplay between canine and wolf lineages. This discrepancy is evidence of multiple rounds of gene transfer in the past.

Imprints on Physique and Personality

The researchers found that wolf genes are linked to a variety of dog traits, most notably body size. Larger dogs tend to have more wolf ancestry, and certain working breeds, such as Arctic sled dogs, wild-dog breeds, and hunting dogs, are more likely to have this trait. Terriers, bird dogs , and scent hounds, on the other hand, were least influenced by wolf genes.

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

On the other hand, even the Chihuahua, the world’s smallest dog breed, was found to have a small proportion of wolf ancestry, about 0.2 percent. These differences speak to the historical specificity of the breed’s evolution.

The personalities of dog breeds also showed striking patterns depending on the proportion of wolf genes they had. When compared with 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,” “willing to obey,” “easy to train,” and “affectionate.”

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

Adaptive Genes That Support Survival

Wolf-derived genes are not simply a remnant of evolution, but may actually contribute to the survival of dogs. When gene ontology analysis was performed on the regions of the village dog genome that were enriched for wolf ancestral elements, the only significant functional category was the olfactory transduction pathway. This result suggests that gene inflow from wolves may have enhanced the village dog’s sense of smell, thereby improving its ability to search for human food waste.

Village dogs that are not directly cared for by humans generally have a very low survival rate. For stray dogs in urban environments, 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 may play a key role in their survival in these harsh environments.