The genes that underlie the dog’s liking of human company—call them sociability genes—have human analogs. Curiously, in humans, variations in these sociability genes appear to play a role in human disorders such as autism and aggression related to attention-deficit/hyperactivity disorder (ADHD).
The genes were highlighted in a new study that searched through the dog genome for genetic variants that could explain human-directed social behaviors. This study, which was conducted by scientists at Linköping University, found genomic patterns that appear to coincide with the tendency of dogs to seek human assistance when presented with a difficult problem—opening a tightly sealed container to obtain a treat.
Although many studies have evaluated the dog’s social skills, including the ability to read human facial expressions, the current study is unusual. It is, according to the Linköping scientists, the first genome-wide association study (GWAS) to present candidate genomic regions for dog sociability and interspecies communication.
Detailed results appeared September 29 in the journal Scientific Reports, in an article entitled, “Genomic Regions Associated with Interspecies Communication in Dogs Contain Genes Related to Human Social Disorders.” The article described how individuals in a population of beagles—bred, kept, and handled under highly standardized conditions—were evaluated for their willingness to initiate contact with humans during an “impossible” task.
Unlike wolves, the authors noted, dogs usually turn to a nearby human in a help-seeking manner when faced with difficult tasks. The authors had previously reported on the significant heritabilities for such behavior. In the present study, the authors used the GWAS method to map candidate genes associated with dogs’ social skills.
Almost 500 dogs participated in the assessment of sociable behavior. And in more than 200 of these dogs, DNA was studied via an HD Canine SNP-chip.
“One genetic marker on chromosome 26 within the SEZ6L gene was significantly associated with time spent close to, and in physical contact with, the human,” wrote the authors of the Scientific Reports paper. “Two suggestive markers on chromosome 26, located within the ARVCF gene, were also associated with human contact seeking.”
Although the Linköping scientists, led by professor of ethology Per Jensen, Ph.D., emphasized that their study was focused on the evolution of domesticated social behavior in dogs, they also considered how their findings might be relevant to humans.
“Strikingly, four additional genes present in the same linkage blocks affect social abilities in humans, e.g., SEZ6L has been associated with autism and COMT affects aggression in adolescents with ADHD,” the authors noted. “These results advance our understanding of dog domestication and raise the use of the dog as a novel model system for human social disorders.”
Ultimately, the scientists found a relationship between five different genes and the ability to interact with humans. For four of these genes, human analogs exist that are associated with human social disorders.
The current study included just one dog breed, the beagle. This within-breed approach has the advantage of reducing locus heterogeneity, similar to what is seen in studies of geographically isolated human populations in countries such as Iceland or Finland. Yet the investigators are looking forward to broadening their work. “If the associations we have found can be confirmed in other dog breeds,” noted Dr. Jensen, “it is possible that dog behavior also can help us to better understand social disorders in humans.”