Scientists say they have 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 on Wednesday.

Reporting in the journal Nature, the team said the tale began 10 years ago, with the discovery of a piece of fossilised 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 centimetres long by eight centimetres wide.”

The result is the oldest genome that has been fully sequenced – from an animal that lived between 560,000 and 780,000 years ago.

“Our analyses suggest that the Equus lineage giving rise to all contemporary horses, zebras and donkeys originated four to 4.5 million years before present, twice the conventionally accepted time,” the study says.

It also suggested that efforts to preserve the Przewalski’s horse, by crossing it with domestic breeds, are genetically valid. There seems to be have been little genetic intrusion into the wild variant.

Beyond this immediate discovery, the scientists are confident their work will one day shed light on prehistoric animals or even our own forebears, through fossils whose DNA is conventionally considered too degraded for sequencing.

“In very cold conditions, roughly 10 per cent of small-sized molecules have a good chance of surviving beyond a million years,” said Orlando.

Read more: http://www.smh.com.au/technology/sci-tech/on-the-hoof-ancient-dna-reveals-story-of-horse-that-lived-700000-years-ago-20130628-2p0zm.html#ixzz2XlIHhH7F

http://www.nature.com/nature/journal/vaop/ncurrent/full/nature12323.htm

>“In very cold conditions, roughly 10 per cent of small-sized molecules have a good chance of surviving beyond a million years,” said Orlando.

That’s encouraging but it presumably means the animal had to live and die in cold conditions that then remained cold up to the present day.

Interesting the horse evolved in North America, went extinct there, but reintroduced by Europeans.