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 mitochondrial DNA and Y-chromosome phylogenetic trees revealed complex interactions between canine and wolf lineages. This variation is evidence of many rounds of gene transfer in the past.
Physical Characteristics and Personality
Researchers found that wolf genes are linked to dog traits, especially body size. Large 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, are not heavily influenced by wolf genes.
Notably, among the large service dogs, the influence of wolf ancestry varied greatly between breeds. The Sarabi Dog, Central Asian Shepherd Dog, and Anatolian Shepherd Dog, which are herding 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.
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. This difference speaks to the evolutionary history of the species.
The personalities of dog breeds also showed striking patterns depending on the amount of wolf genes they possessed. When compared to certain breed individuals defined by the Kennel Club, the organization responsible for certifying dog breeds, breeds with a few wolf genes were more likely to be described as “friendly,” “willing to obey,” “easy to train,” and “loving.”
In contrast, strong wolf breeds were often described as “suspicious of strangers,” “independent,” “cautious,” and “territorial.” However, the researchers cautioned that these explanations are based on human observations and it is not clear whether the wolf DNA is directly related.
Adaptive Genes That Support Survival
The genes carried by wolves are not just a vestige of evolution, but may actually contribute to the survival of dogs. When gene ontology analysis was performed on regions of the village dog genome that were enriched for wolf ancestral traits, the only significant functional category was the olfactory tract. This result suggests that the introduction of genes from wolves may improve the rural dog’s sense of smell, thereby improving its ability to search for human food scraps.
Rural dogs without direct human care often have a very low survival rate. For dogs lost in urban areas, the survival rate at five months of age is less than 37 percent, and some reports suggest it is as low as 16 percent. A keen sense of smell may play an important role in their survival in these harsh environments.
