Where and when dogs arose is one of the biggest mysteries of domestication. To solve it, researchers have tried everything from analyzing ancient dog bones to sequencing modern dog DNA—all with inconclusive results. Now, researchers have tried a new tack: figuring out where the ancient wolves that gave rise to dogs lived. The new study doesn’t close the case, but it does point to a broad geographic region—eastern Eurasia—while also suggesting our canine pals may have been domesticated more than once.
That region “certainly jibes with what I’ve been thinking,” says Adam Boyko, a canine geneticist at Cornell University who wasn’t involved in the work. He remains skeptical, however, about the possibility of separate domestication events.
At least 15,000 years ago—and perhaps closer to 23,000 years ago—humans and wolves began their fateful dance toward domestication. This was during the last ice age, when high-latitude regions experienced a bitterly cold, dry climate. According to the most prominent theory, less timid gray wolves inched closer and closer to human campsites to get scraps. Over time, they passed along genes for increasingly docile behaviors and traits. Humans found these newfound friends useful for hunting and guarding campsites.
Exactly where this happened is hotly contested. Some genetic analyses of modern dogs suggest they arose in East Asia, whereas other genetic and archaeological evidence indicates our pups came from Siberia, the Middle East, Western Europe, or perhaps multiple places. “There’s been a lot of pins put in the map,” says Pontus Skoglund, a geneticist at the Francis Crick Institute and senior author of the new study.
Skoglund and a vast cast of collaborators from 16 countries decided to try something new: build a massive map of wolf ancestry around the time of domestication. “If you imagine wolf ancestry as a big jigsaw puzzle, we placed the dog puzzle piece within that map,” he says.
The paper’s 81 co-authors—mostly archaeologists, anthropologists, and geneticists—pooled their collective resources and sequenced 66 ancient wolf genomes and incorporated six previously published ones, from sites across Europe, Siberia, and North America. The ages of these animals spanned the past 100,000 years. Next, the team used computer software to compare the 72 ancient genomes and work out a rough family tree.
One of the first things that jumped out was how interconnected these far-flung wolf populations remained over time, Skoglund says. Over tens of thousands of years, wolves living as far apart as Alaska and Europe continued to share recent ancestry, suggesting the animals were mobile and mated at least occasionally.
