Five genes present in the dog's DNA, five reasons that science identifies as essential to understanding the close relationship that has always bound it to humans. This is the finding of a study from Linköping University in Sweden, recently published in the journal Scientific Reports. By analysing the DNA of 190 beagle dogs, Swedish researchers discovered five specific genes that underlie the empathetic behaviour of our four-legged friend towards humans.

What the experiment demonstrates

In one of the experiments carried out, for example, dogs were placed in front of a task that required them to interact with their trainer. The animals had to slide three lids along the ground, one of which was locked and could not be removed. Confronted with the impossibility of completing the task, the selected dogs turned towards the person supervising them, looked them in the eye and sought close visual contact. Observing this behaviour, the researchers noted how the animals were seeking practical help from the person, or a verbal cue to help them solve the problem. The genome of the dogs subjected to these tests was subsequently analysed, and the researchers found within it a genetic marker in the Sez6l gene. This gene was found to be associated with the time the dog spends in a domestic environment and in close contact with people. In addition, other markers in the Arvcf gene were linked to the seeking out and enjoyment of close contact with human beings. The relationship and bond between humans and dogs has therefore been codified and demonstrated from a genetic standpoint as well.

In the dog's DNA, the secret of a friendship thousands of years in the making

Archaeological research also confirms the intimate relationship between humans and dogs. A prehistoric dog's tooth was found in an area of Great Britain where archaeological excavations had already been carried out. It was an important, if foreseeable, turning point in the ongoing effort to understand the relationship between humans and domesticated animals. The tooth appears to belong to a large dog — a kind of wolf-dog, similar in size and appearance to a modern German shepherd. The prehistoric dog died (whether from old age or from some injury is unknown) roughly 350 kilometres from the present-day town of York, in the United Kingdom, near a tiny human settlement where the dog is believed to have lived alongside its human companion, most likely a hunter with whom the animal went hunting.

More complex research carried out on the animal's DNA made it possible to discover that the dog had followed a diet based on aurochs, a large wild mammal now extinct and considered the ancestor of the domestic cow. Prehistoric humans fed on aurochs, hunting them with bows and arrows — and not alone, as the find clearly demonstrates. The large wolf-like dog helped to flush out and chase down the prey, which was then finished off by the hunters and their weapons. The isotope found in the tooth enamel revealed another surprising detail.

The discovery after more than seven thousand years

After more than seven thousand years, it was able to show that the tooth found did not belong to a local dog, but to an animal that had come from very far away, most likely following hunters who had moved on in search of prey and new territories to settle. As Professor Bryony Rogers, one of the researchers who studied the find, explained to The Times of London, the dog came from a place very far from where it was found. The oxygen isotope contained in the tooth enamel is influenced by latitude, temperature and even the level of humidity and rainfall recorded in the soil. For the prehistoric dog's tooth, these values did not match those that would have been expected in the tooth of an animal born and raised near the site of the find. At this point, the British researchers concluded that the find not only demonstrates the centuries-old friendship and collaborative relationship between humans and dogs, but also sheds light on the daily work that humans and dogs carried out together. For more than seven thousand years, the bond of love and loyalty that dogs show towards us has remained unchanged, attested not only by paintings and graffiti, but also by the remains that our four-legged companions have left behind in what were once the camps and settlements of early humans.