A vast genetic and behavioral study carried out in Japan recently made it possible to identify two mutations at the origin of the adaptations which allowed the integration of the dog into human society.
Although scientists have long assumed that changes in different genes, including those controlling hormones that influence social behavior, played a fundamental role in the domestication of dogs, they have so far failed to identify the genetic mechanisms specific to the origin of this process.
As part of the work detailed in the review Scientific reportsa team of researchers from theazabu university discovered that two mutations in the melanocortin 2 receptor gene, involved in the production of cortisol (the stress hormone), were involved in the development of skills that allow dogs to interact and communicate effectively with humans.
The researchers used two tasks to examine the social and cognitive interactions of 624 domestic dogs. In the first food, designed to test the understanding of gestures and human communication, the latter had to decide which of two bowls contained something hidden under it, based on clues given by the experimenters (look, pointing, tapping…).
In the second, the dogs were given a problem-solving test, consisting of trying to open a container to access the food. During this, the scientists measured how often and for how long the dogs stared at the experimenters to assess their social attachment to humans.
An attachment conditioned by genetic mutations
The dogs had been separated into two groups, based on their breed: the group of ancient breeds, probably genetically closer to wolves, such as the siberian husky and theakita, and the general group, encompassing all other races. While experiments showed that members of the first group spent less time looking at humans during the second task, suggesting less attachment, no significant race-related differences were found during the first.
The team then looked for differences in genes associated with human-related social cognition, including genes for oxytocin, oxytocin receptors and melanocortin 2 (MC2R), as well as a gene called WBSCR17playing an essential role in the syndrome of Williams-Beurencharacterized by hypersocial behavior in humans.
Experts have found that two changes in the gene MC2R were associated with correctly interpreting gestures on the first task and looking more often at the experimenters on the second. This suggests that this gene significantly compensated for the domestication of dogs, probably by promoting lower stress levels in the presence of humans.