NEW YORK (AP) — Delving into the oldest canine genetics explored so far, researchers are uncovering more proof that dogs have been human companions for millennia.

Experts believe that dogs evolved from an ancient lineage of gray wolves that roamed Europe or Asia. These wolves, thousands of years ago, began to cohabitate with humans, becoming less fierce and more domesticated over time. This transformation in their genetics and behavior eventually led to the dogs we cherish today.

The precise details of when and where this transformation occurred remain elusive. To unravel these mysteries, scientists are analyzing DNA fragments from ancient canine and wolf remains to reconstruct the appearance and origins of the earliest dogs.

In a pair of studies unveiled Wednesday in the journal Nature, researchers have managed to extend the timeline further back. By developing a novel approach to study ancient canine DNA, often challenging to extract due to contamination, they focused specifically on extracting the canine-specific sequences.

These investigations examined ancient genetic material from over 200 dog and wolf specimens, with the oldest samples dating back approximately 15,800 years, pushing the origins of dogs back by at least 5,000 years.

“The enduring bond between humans and dogs has existed for such an extensive period and continues to thrive,” remarked Jeffrey Kidd, a dog genomics specialist at the University of Michigan, who did not participate in the recent studies.

The genes showed that dogs were already spread out across Western Europe and Asia 14,200 years ago, at a time before agriculture and farming. These dogs lived with hunter-gatherer humans who were constantly on the move.

The dawn of agriculture — a major shift in human history — brought new people to Europe from southwest Asia. They mixed and mingled with Europeans, leaving a lasting and varied imprint on their genes.

But the dog genes studied by the scientists, stretching from the United Kingdom all the way to Turkey, stayed more consistent. They were less impacted by the arrival of new humans during the development of agriculture, and more by interactions between different hunter-gatherer groups and their dogs thousands of years before.

That’s different from dogs in Asia and the Americas, whose genes more closely reflect the movement patterns of their owners.

Scientists don’t know exactly what the first dogs looked like, but they have some ideas.

“We’re suspecting they would have resembled smaller wolves,” said study co-author Lachie Scarsbrook with the Ludwig Maximilian University of Munich.

It’s also not clear how these ancient dogs lived alongside their humans. They could have stood guard or helped them hunt, but probably also played with young children.

There’s still more work to go to pinpoint exactly when dogs emerged — the first few pages of a storied relationship that’s still going strong.

“They are humanity’s best friend, alongside our societies for the last 16,000 years and will continue to in the future,” Scarsbrook said.