How did dogs get to the Americas? An ancient bone fragment holds clues


This bone fragment, present in Southeast Alaska, belongs to a canine that lived about 10,150 years in the past, a research concludes. Scientists say the stays, a bit of a femur, present perception into the query of when dogs and people first entered the Americas, and what route they took to get there. Credit: Douglas Levere / University at Buffalo

The historical past of dogs has been intertwined, since ancient occasions, with that of the people who domesticated them.

But how far again does that historical past go in the Americas, and which route did dogs use to enter this a part of the world?

A brand new research led by the University at Buffalo offers perception into these questions. The analysis stories {that a} bone fragment present in Southeast Alaska belongs to a canine that lived in the area about 10,150 years in the past. Scientists say the stays—a bit of a femur—characterize the oldest confirmed stays of a home canine in the Americas.

DNA from the bone fragment holds clues about early canine historical past on this a part of the world.

Researchers analyzed the canine’s mitochondrial genome, and concluded that the animal belonged to a lineage of dogs whose evolutionary historical past diverged from that of Siberian dogs as early as 16,700 years in the past. The timing of that cut up coincides with a interval when people could have been migrating into North America alongside a coastal route that included Southeast Alaska.

The analysis will likely be printed on Feb. 24 in the Proceedings of the Royal Society B. Charlotte Lindqvist, an evolutionary biologist from UB, was senior creator of the research, which included scientists from UB and the University of South Dakota. The findings add to a rising physique of information about the migration of dogs into the Americas.

How did dogs get to the Americas? An ancient bone fragment holds clues
A map exhibiting the research space. Credit: Bob Wilder / University at Buffalo

“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, Ph.D., affiliate professor of organic 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 Ph.D. pupil in organic sciences, and considered 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.”

A shock discovering from a big assortment of bones

Lindqvist’s group did not set out to research dogs. The scientists got here throughout the femur fragment whereas sequencing DNA from a group of a whole bunch of bones excavated years earlier than in Southeast Alaska by researchers together with Timothy Heaton, Ph.D., 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, initially thought to come from a bear, was fairly small, however when the DNA was studied, the group realized it was from a canine, Lindqvist says.

How did dogs get to the Americas? An ancient bone fragment holds clues
Flavio Augusto da Silva Coelho, a University at Buffalo PhD pupil in organic sciences, holds the ancient canine bone fragment that was present in Southeast Alaska. Credit: Douglas Levere / University at Buffalo

After this shock discovery, the scientists in contrast the bone’s mitochondrial genome to these of different ancient and fashionable dogs. This evaluation confirmed that the Southeast Alaskan canine shared a typical ancestor about 16,000 years in the past with American canines that lived earlier than the arrival of European colonizers, Lindqvist says. (Mitochondrial DNA, inherited from the mom, represents a small fraction of an organism’s full DNA, so sequencing an entire nuclear genome may present additional particulars if that materials might be extracted.)

Of curiosity, carbon isotope evaluation on the bone fragment signifies that the ancient Southeast Alaskan canine seemingly had a marine weight loss program, which can have consisted of meals comparable to fish and scraps from seals and whales.

The analysis provides depth to the layered historical past of how dogs got here to populate the Americas. As Lindqvist notes, canines did not arrive abruptly. For instance, some Arctic dogs arrived later from East Asia with the Thule tradition, whereas Siberian huskies have been imported to Alaska throughout the Gold Rush. Other dogs have been introduced to the Americas by European colonizers.

The new research sharpens the debate on canine and human migration into the Americas.

“Our early dog from Southeast Alaska supports the hypothesis that the first dog and human migration occurred through the Northwest Pacific coastal route instead of the central continental corridor, which is thought to have become viable only about 13,000 years ago,” Coelho notes.

First dogs in the Americas arrived from Siberia, disappeared after European contact

More data:
An early canine from Southeast Alaska helps a coastal route for the first canine migration into the Americas, Proceedings of the Royal Society B, rspb.royalsocietypublishing.or … .1098/rspb.2020.3103

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How did dogs get to the Americas? An ancient bone fragment holds clues (2021, February 23)
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