When it comes to diversity in shape and stature, few single species show as much variety as dogs. From dinky toy poodles to towering Great Danes, dog breeds come in nearly every shape and size. Now, according to a new study, the same genetic plasticity that produces so many breeds could also make dogs more susceptible to mental conditions comparable to obsessive-compulsive disorder and autism.
As one of the oldest domesticated species, dogs have been bred over thousands of years while living and communicating with humans. Scientists have long been puzzled, however, as to how ancient humans transformed wild, independent wolves into fluffy pups desperate for hugs and pets, Nicola Davis reports for The Guardian.
“[Our aim] is to try to understand the genetic underpinnings of domestication: what is it that has helped to turn the wolf, which is really not interested in humans to start off with, into this extremely sociable creature, which is the dog?” Per Jensen, a researcher at Sweden’s Linköping University, tells Davis. “We think we have at least found some of the genetic background of this process.”
In a new study, published in Scientific Reports, Jensen and his colleagues attempted to figure out what genes were behind this friendliness by giving 437 canine subjects an unsolvable task that involved opening three containers of food. While two of the containers could easily slide open, the third was secured in such a way that only a human could get at the treats. Jensen and his team watched to see if the dogs would seek help or comfort from a nearby human when they started having trouble with the sealed lid, Phys.org reports.
“We know that wolves don’t seek help, they will attempt to solve the problem on their own, and some dogs actually do that—they just keep going and trying to open this lid,” Jensen tells Davis. “But the most common reaction is at some point to turn to the human.”
After the test was over, Jensen’s teams took the 95 most socially adept beagles and the 95 most independently-minded pups and sequenced their DNA. When the researchers compared these DNA samples, they discovered two regions that appear to be associated with the dog’s desire for human contact. Intriguingly, these sections of DNA also contained five genes that have been linked to some human mental disorders, including OCD and autism, Jennifer Viegas reports for Seeker.
"With respect to autism-like disorders, not much has been done, but OCD is a great problem in particular in some breeds of dogs,” Jensen tells Viegas. “Dog psychologists usually have training programs that can alleviate some of these problems."
To be clear, these conditions are very complex—research suggests that there are probably more than 100 genes associated with disorders like autism and schizophrenia and this doesn’t mean that dogs can experience the same symptoms as people.
It does suggest, however, that dogs could be used in laboratory conditions as models for studying social behavior for humans, much like pigs and rats are used to model medical conditions, Viegas reports. Jensen also notes that the dog’s ability to be bred into such different shapes and sizes could make it easier for them to develop mutations that could lead to issues with their mental and physical health.
While more research needs to be done, studying man’s best friend could help researchers make strides in learning how our brains and bodies work.