DNA from ancient frozen caribou bones found in the Yukon suggests caribou herds in the area were displaced by a volcanic eruption 1,000 years ago.

Most woodland caribou herds in Canada are threatened. (Mountain Caribou Project) Researchers from the U.S., U.K. and Canada have found that DNA from caribou remains found in the Whitehorse area older than 1,000 years doesn't match the DNA of the current population there.

The period when the ancient herd roamed the area corresponds roughly to the time when two eruptions of the Mount Churchill volcano occurred in southern Alaska near the Yukon border. The eruptions covered much of east-central Alaska and the Yukon with a layer of ash that geologists call the White River tephra.

Tyler Kuhn, a graduate student at Vancouver's Simon Fraser University who is originally from Whitehorse, recovered short strands of DNA from caribou bones found in ice patches in the Yukon, just north of the B.C. border.

Kuhn and his colleagues from the University of Oxford, the University of Alaska Fairbanks, King's University College in Edmonton and Pennsylvania State University compared the ancient DNA to that of caribou living in the area today and found it didn't match.

The local population isn't related to herds currently living to the north, east or west, either, the researchers said.

They concluded that the herd is a recent arrival to the area, possibly from farther south.

Kuhn said several caribou herds that live in woodlands in Canada are threatened so research into their population is important for conservation.

"Understanding the relationships among herds is important, but understanding how herds react to environmental changes through time is equally necessary for us to manage caribou properly," he said in a statement.

The volcanic eruptions that deposited the White River tephra are associated with other changes in the region at the time, such as the First Nations hunters' transition from using the atlatl dart thrower to the more efficient bow-and-arrow.