Horse Fossil Yields Astonishingly Old Genome—Are Similarly Ancient Human Genomes Next?

Horse fossil dating to around 700,000 years ago has yielded the oldest complete genome yet. Image: D. G. Froese

Researchers have recovered DNA from a nearly 700,000-year-old horse fossil and assembled a draft of the animal’s genome from it. It is the oldest complete genome to date by a long shot–hundreds of thousands of years older than the previous record holder, which came from an archaic human that lived around 80,000 years ago. The genome elucidates the evolution of modern horses and their relatives, and raises the question of whether scientists might someday be able to obtain similarly ancient genomes of human ancestors.

Ludovic Orlando of the University of Copenhagen and his colleagues extracted the DNA from a foot bone found at the site of Thistle Creek in Canada’s Yukon Territory in permafrost dating to between 560,000 and 780,000 years ago, which falls within the so-called early Middle Pleistocene time period. They then mapped the fragments of DNA they obtained against the genome of a modern horse to piece together a draft of the ancient horse’s genome.

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