Ancient DNA shows story of the horse

PARIS - Agence France-Presse

This photo shows two pieces of a 700,000-year-old horse metapodial bone.

Scientists on June 26 said they had unraveled the DNA of a horse that lived some 700,000 years ago, a record-breaking feat in the young field of palaeo-genomics.

The ancient find indicates that all horses today, as well as donkeys and zebras, shared a common ancestor that lived some four million years ago, twice as early as thought.

The breakthrough also raises hopes that many fossils deemed useless for DNA sampling may in fact be crammed with genetic treasure, researchers said.

Reporting in the journal Nature, the team said the tale began 10 years ago, with the discovery of a piece of fossilized horse bone in the permafrost at a location called Thistle Creek, in Canada’s Yukon territory.

“It’s a piece of metapodial bone” from the leg, said Ludovic Orlando, a French researcher at the Centre for Geogenetics at Denmark’s Museum of Natural History. “It’s a fragment about 15 centimeters long by eight centimeters wide.”

Radiodating of the ground in which the bone was found indicates that the organic material there, decomposed leaves and so on, was deposited about 735,000 years ago.

The sample had been astonishingly preserved in the deep chill but time was bound to have damaged its cells and thus limit chances of teasing useful DNA out of it.