BUFFALO, N.Y. — The history of dogs has been intertwined, since ancient times, with that of the humans who domesticated them.

But how far back does that history go in the Americas, and which route did dogs use to enter this part of the world?

A new study led by the University at Buffalo provides insight into these questions. The research reports that a bone fragment found in Southeast Alaska belongs to a dog that lived in the region about 10,150 years ago. Scientists say the remains — a piece of a femur — represent the oldest confirmed remains of a domestic dog in the Americas.

DNA from the bone fragment holds clues about early canine history in this part of the world.

The research was published on Feb. 24 in the Proceedings of the Royal Society. Charlotte Lindqvist, an evolutionary biologist from UB, was senior author of the study, which included scientists from UB and the University of South Dakota. The findings add to a growing body of knowledge about the migration of dogs into the Americas.

“We now have genetic evidence from an ancient dog found along the Alaskan coast. Because dogs are a proxy for human occupation, our data help provide not only a timing but also a location for the entry of dogs and people into the Americas. Our study supports the theory that this migration occurred just as coastal glaciers retreated during the last Ice Age,” says Lindqvist, PhD, associate professor of biological sciences in the UB College of Arts and Sciences. “There have been multiple waves of dogs migrating into the Americas, but one question has been, when did the first dogs arrive? And did they follow an interior ice-free corridor between the massive ice sheets that covered the North American continent, or was their first migration along the coast?”

“The fossil record of ancient dogs in the Americas is incomplete, so any new remains that are found provide important clues,” says Flavio Augusto da Silva Coelho, a UB PhD student in biological sciences, and one of the paper’s first authors. “Before our study, the earliest ancient American dog bones that had their DNA sequenced were found in the U.S. Midwest.”

Lindqvist’s team did not set out to study dogs. The scientists came across the femur fragment while sequencing DNA from a collection of hundreds of bones excavated years before in Southeast Alaska by researchers including Timothy Heaton, PhD, professor of earth sciences at the University of South Dakota.

“This all started out with our interest in how Ice Age climatic changes impacted animals’ survival and movements in this region,” Lindqvist says. “Southeast Alaska might have served as an ice-free stopping point of sorts, and now — with our dog — we think that early human migration through the region might be much more important than some previously suspected.”

The bone fragment, originally thought to come from a bear, was quite small, but when  the DNA was studied, the team realized it was from a dog, Lindqvist says.

The research adds depth to the layered history of how dogs came to populate the Americas. As Lindqvist notes, canines did not arrive all at once. For example, some Arctic dogs arrived later from East Asia with the Thule culture, while Siberian huskies were imported to Alaska during the Gold Rush. Other dogs were brought to the Americas by European colonizers.