When it comes to mapping equine genomes, researchers’ test horses seem to be getting older: In 2007 it was a 3-year-old gray Thoroughbred marecalled Twilight from New York. In 2012 it was 18-year-old Sugar, a Quarter Horse mare from Texas.

Now in 2013 it’s Thistle Creek, a Middle Pleistocene stallion from the Yukon permafrost near the eastern Alaskan border. He’s roughly 700,000 years old. That makes Thistle Creek—named for the excavation site where his leg bone fragment was discovered—the oldest equine to have its DNA fully sequenced.

And actually, Thistle Creek’s DNA is the oldest DNA of any species to be fully sequenced. The second oldest? 110,000-year-old polar bear DNA.

Ludovic Orlando, PhD, HDR, associate professor in the Centre for GeoGenetics Paleomix Group at the University of Copenhagen’s Natural History Museum of Denmark, led an international team of 56 scientists listed as co-authors of the groundbreaking study