New insights into how genetic changes may have shaped dog domestication
Two mutations in a single gene linked to the body’s stress response appear to have helped shape how dogs became companions to humans. These genetic tweaks may have enabled dogs to develop social awareness and the ability to communicate effectively with people, assisting them in forming bonds with human caregivers.
A study published in Scientific Reports and led by researchers from the University of Azabu in Japan points to alterations in the melanocortin 2 receptor gene, MC2R, as a possible factor in easing tension around humans. The work suggests that these mutations could contribute to lower stress responses when dogs are in proximity to people, a trait that would support closer social interactions.
Domestication likely involved a suite of genetic changes across multiple genes, many of which are connected to hormonal pathways that influence social behavior. Yet the exact genetic mosaic responsible for domesticated dogs’ social abilities has remained unclear.
The research team, headed by Miho Nagasawa, explored how social cognition unfolds in everyday canine life by studying 624 pet dogs through two distinct tasks. In the first task, dogs were asked to determine which bowl concealed food based on human cues such as gaze, pointing, and gestures. This setup evaluated the dogs’ capacity to interpret human signals and use social information to guide problem solving.
In the second task, dogs attempted to access food from a container, while researchers tracked how often and how long the dogs looked to or interacted with the humans present. These measures served as proxies for social attachment and the strength of human-dog social bonding.
Participants were divided into two breed-based groups. The Ancient group includes breeds considered genetically closer to wolves, such as the Akita and the Siberian Husky. The general group comprises a broader mix of breeds that are more distant from wolf ancestry. The distinction allowed researchers to examine how deep evolutionary lineage might influence social behavior in modern dogs.
Notably, dogs from the Ancient group tended to spend less time looking at people during the problem-solving task. The university clarified that this difference did not reflect broad race-related disparities in the first assignment, but it did hint at variations in how closely coupled certain breeds are to human cues during problem solving.
The study also compared genetic profiles associated with social cognition between the two groups. The researchers focused on genes linked to social and affiliative behaviors in humans, including oxytocin and its receptor, as well as MC2R. The aim was to determine whether these genes show parallel roles in dogs’ social interaction with humans.
Two changes in the MC2R gene correlated with a higher likelihood of correctly interpreting human gestures in the initial task. In practical terms, dogs carrying these MC2R variants appeared to attend more to people during problem solving, suggesting a closer integration of social processing with cognitive tasks.
These findings contribute to a broader understanding of how hormonal and neural mechanisms can shape the evolution of cooperation between species. They imply that a modest shift in stress modulation within dogs may have supported more nuanced and reliable social communication with humans, a foundation for the cooperative companionship seen today. The researchers emphasize that the results are part of a larger picture involving multiple genetic pathways and environmental experiences that together guided domestication and social adaptation. [Attribution: Scientific Reports, University of Azabu]