Scientists Study DNA to Uncover Man's Ancient Bond With Dogs
Whenever science finds a way to explain something we thought didn’t need explaining or maybe even just assumed there was no tangible answer for, I’m intrigued. For example, why are we so infatuated with dogs? Our love for them is ubiquitous, just like their affection toward us seems natural and instinctive, meaning there must be some reason and purpose for it all.
For centuries, mankind has looked at how the bond between humans and canines came to be, mostly drawing conclusions from sociological factors that fed an evolutionary partnership between the species.
According to archeologist Diane Perlov, senior vice president for exhibitions at Los Angeles’ California Science Center, the pairing goes back more than 10,000 years. Both species would have recognized that the other was good at hunting, Perlov, describes. Humans and dogs/wolves are pack animals, meaning they are social creatures that thrive on cooperation and relationships with others. It’s how we each evolved as hunters, and so the partnership is understood to have started off as a match made in evolutionary heaven, but whether or not wolves offered their services in exchange for security or humans made a conscious effort to domesticate them for their own benefit is one major question that remains unknown.
Last month, a study conducted at the Wolf Science Center in Vienna revealed that one major genetic difference between wolves and domesticated dogs is a simple instinct to “take the lead” when cooperating with humans. Wolves, they found, are more inclined to take initiative and carry out tasks on their own accord, while domesticated dogs are more likely to wait for direction from their human partner or rely on their human to make the first move altogether. In the big picture, it gives us a little insight into how the bond started to form between both species thousands of years ago. The researchers suggested that domesticated dogs became so specifically because humans started selectively breeding the animals which were most likely to cooperate. This helped minimize conflicts between humans and dogs by establishing a dynamic in which humans lead and our four-legged-friends follow.
Today, we value dogs because of the depth of companionship they offer us, but that bond was first necessary for everything from guarding our homes to cooperating on hunts, and the domestication of other animals has allowed humans to travel faster, given us more accessible sources of food, and work the land or agriculture. So domestication of animals has long been a major key in human evolution.
Even newer research has now dug into something a little more tangible than dissecting social interactions: DNA. Researchers in Europe obtained the DNA from the remains of both wild and domesticated animals that lived thousands of years ago. They compared that DNA with that of modern domesticated animals like pigs, chickens, and of course, dogs.
"These three animals can tell us a lot about the beginning of domestication and the changing association they had with people," said Professor Greger Larson, a palaeogeneticist at the University of Oxford in the UK and coordinator of the UnDEAD project. "Dogs were the first animals to be domesticated, chickens were the earliest birds that we have evidence of domestication for and pigs were some of the earliest farm animals to be domesticated.”
The project found that there may not have necessarily been one domestication of dogs as a whole, which many believe started with wolves about 15,000 years ago. The unDEAD project surveyed the DNA from 59 different ancient dogs and one dog from the Bronze Age in Ireland (about 4,800 years ago), to reveal that dogs may have been domesticated as a species on more than just one occasion. In other words, there was no single root domestication of a single species that evolved into domesticated dogs as we know them today.
What researchers now believe is that wolves were domesticated independently through two separate populations in both Eastern and Western Asia.
"We are still getting a tonne of data coming in every week, so my thinking is evolving all the time and swinging like a pendulum all over the place," said Prof. Larson. "It isn't quite giving us a coherent picture yet, but we are getting many more pieces of this giant jigsaw puzzle than we could have dreamed when we started this project."
The population of domesticated dogs from Eastern Asia was found to have arrived in Europe between 6,400 and 14,000 years ago, partially replacing the local paleolithic dog population but also mixing with them. They say that the dogs didn’t arrive on their own, they were brought to Europe along with Neolithic farmers that were migrating to Europe at the time. Pigs, cows, sheep, and goats came with them around the same time.
"Prior to the arrival of the Europeans in the 16th century, the dogs in the Americas had a lineage that descended from East Asia, possibly eastern Siberia," said Prof. Larson. "When the Europeans arrive though, these dogs just disappear, either through persecution or disease or something else.
The findings have been teaching researchers a lot about our relationships with all kinds of domesticated animals on both a social and evolutionary level. "What is fascinating is that the relationship between humans and these animals in the past was probably very different from the one we have today," said Prof. Larson. "Eating chickens is a recent phenomenon, and perhaps only started when they came into Europe in around 700BC. They were probably drawn to humans initially for other reasons (such as easy access to food) and that relationship changed through time.”
"We wondered if this epigenetic inheritance might be partly responsible for the huge variation we see in dogs today," said Dr. Smith, who conducted his research as part of the EpiCDomestic project. "We see it playing a role in domesticated plants, so thought it might too in dogs. The findings are still very preliminary," said Dr. Smith. "We need to do a lot more work to understand exactly how dogs have been changed by living with us."