20 July, 2017
Our loyal, slobbering pets rescue those in need and are extremely social, but until Wednesday, we never figured out why dogs and humans get along so well. Through sequencing DNA from these blood samples and comparing them to how the dogs performed in the behavioral tests, vonHoldt and Udell were able to show significant differences in the drive to socialize with humans between dogs and wolves, according to the study. In short, the scientists report that genetic mutations leave dogs in a state of childlike social and cognitive development where they seek out contact and attention.
Princeton University biologist Bridgett vonHoldt has spent much of her career studying genetic structures of canines, trying to figure out just what makes a dog a dog. In particular, they found mutations on a gene called WBSCR17, which vonHoldt says she studied back while working on her doctoral thesis, and two transcription factor genes.
What is most important: looks, brains or personality? But major differences were also found in WBSCR17, a gene linked to Williams-Beuren syndrome in humans.
"Dogs spend a lot of time looking at a human and wolves spend very little time", vonHoldt says. Dogs were more likely to exhibit human-directed behavior and seek out the assistance of humans during the tests. "This is another piece of the puzzle suggesting that humans did not create dogs intentionally, but instead wolves that were friendliest toward humans were at an evolutionary advantage as our two species began to interact". For instance, it can lead dogs to experience separation anxiety more often than other animals. While this shift in focus was indicative of the social nature of dogs, the dogs also struggled to open the box when there wasn't a person around.
The finding of genetic changes linked to sociability in dogs shows how their friendly behaviour might have evolved. They lick us, jump on us, would probably buy us a house if they could. VonHoldt had in an earlier study had found that dogs did have a similar gene sequence as the WBSCR. "I think that would answer so many questions about domestic species!" Genetic assessment was made alongside at the laboratories and a correlation was made. An integrative approach using both behavioral and genetic data is required to understand the molecular underpinnings of the various behavioral characteristics associated with domestication. One of the gene regions that piqued her interest can be found on chromosome 6.
Williams-Beuren syndrome is a developmental disorder that affects people's facial features and causes a range of health problems including heart defects and abnormalities in the brain and nervous system. But they are tantalizing clues in the mystery of dog domestication.
'Those wolves that were tamer and less aggressive would have been more successful at this, and while the humans did not initially gain any kind of benefit from this process, over time they would have developed some kind of symbiotic [mutually beneficial] relationship with these animals, eventually evolving into the dogs we see today'.
It has been previously theorised that the behavioural divergences between dogs and wolves are due to dogs having evolved higher social cognition, but the researchers behind this new study point to mounting evidence of human-socialised wolves demonstrating equal or greater socio-cognitive performance to domestic dogs, while dogs have a clear edge in exaggerated gregariousness, referred to as hypersociability.