Teamwork was crucial in evolution of dogs
Dog owners often say that their pets know their place in the pack — an observation based on the notion that man's best friend descended from the wolf. But it's not as simple as that.
"Dogs' genetic make-up has changed very much, not least when it comes to digestion," says Peter Savolainen, a researcher in population genetics at KTH and SciLifeLab. "Wolves are not dogs, nor vice versa."
Savolainen and his colleagues have recently proven that the dog originated in South East Asia at least 15,000 years ago. But besides the dog's origins and development, he also looked at which genes you would have to change to make a dog from a wolf.
Among the roughly 20,000 genes found in the DNA of both dogs and wolves, one can clearly see that those related to digestion and behavior have changed.
"It's quite logical. Canine psyche must surely be less aggressive to be able to interact with humans. Moreover, eating habits and thus digestion changed. An all-meat diet was adapted to include starch, enabling dogs to eat humans' table scraps," he says.
Why our ancestors chose to domesticate and tame wolves, nobody knows. But there is evidence that such canines existed at least 15,000 years ago. They were used to hunt and guard, and their ability to decipher signals became a valuable trait.
"You could say that domestication is a kind of human-driven evolution. However, it is believed that mutual communication is essential to this process and the dog seems to have been unusually good at controlling human behavior as well," Savolainen says.
Other theories are that wolves, just like homo sapiens, are social, pack animals with clear hierarchies, which made them a good fit for humans.
Dogs are also one of the most important model organisms in terms of examining the human genome.
During the last 500 years, humans have bred various breeds that exhibit differences in appearance and temperament. However, even if the pit bull and Chihuahua appear significantly different, their genetic variation is very small. Some breeds have inherited a number of diseases in the bargain. A gene conferring hanging ears may be coupled to one that provides, for example cancer.
"There is a sharp speeding up of evolution where some breeds have been bred down, and animal welfare became an afterthought," he says.
Surprisingly, Savolainen does not have a dog of his own. He is allergic to them. But he has personally collected DNA from a great number of breeds worldwide to compile one of the world's most important canine gene banks.
The bank is used not only in his daily research, but also in his infrequent role as a forensic expert. Savolainen is one of the few in the world who can analyze dog track from crime scenes. This contribution can help police rule out or clarify relationships between perpetrators and victims.
"Luckily however, I have not been hired so often," he adds. "So far, it might have been about five cases."