Researchers have unraveled the genetic code of a wild horse that loped across the frozen Yukon about 700,000 years ago, making it the oldest creature by far to reveal its DNA to modern science. 
 
 Until recently, experts believed it was impossible to recover useful amounts of DNA from fossils that old. The previous record holder for oldest genome belonged to a polar bear that lived more than 110,000 years ago. The horse sequence, described Wednesday in the journal Nature, amounts to a dramatic increase in how far back scientists can peer into the biochemical history of advanced life. 
 
 The DNA was extracted from a 6-inch slice of a fossilized horse leg bone that was found nine years ago. Under normal conditions, DNA begins to degrade soon after death. But this bone was preserved in permafrost at Thistle Creek in Canada's Yukon Territory. 
 
 Dating techniques revealed that the animal lived in an epoch when woolly mammoths, saber-toothed cats and giant beavers shared turf with ancestral humans. 
 
 The work "opens great perspectives as to the level of details we can reconstruct of our origins and the evolutionary history of every animal on the planet," said study leader Ludovic Orlando of the Center for GeoGenetics at the Natural History Museum of Denmark. 
 
 Orlando and an international team of collaborators pieced together even the tiniest of DNA fragments recovered from the bone. Such genetic puzzle assembly generally includes multiple samples from each part of the genome, sometimes as many as five or 10. In this case, the so-called coverage was just 1.12. 
 
 That's not enough detail to say much about what the horse looked like, said Eske Willerslev, an evolutionary biologist at the Natural History Museum of Denmark who worked on the study. Team members suggested the horse was about the size of a modern Icelandic or Arabian horse, though it probably was less muscular, and perhaps slower. 
 
 "If they were fast runners, it was not because of the same genes we know of today," Orlando said. 
 
 As part of the genetic sleuthing, the team also sequenced the DNA of a 43,000-year-old horse fossil, five modern domesticated horses, a wild Przewalski's horse native to the Mongolian steppes, and a donkey from the Copenhagen Zoo named Willy. 
 
 By comparing all of these genomes, the researchers determined that the most recent common ancestor of all these species — as well as zebras — lived 4 million to 4.5 million years ago. That's about 2 million years earlier than previously thought, and allows for far more time for horses to have evolved into the animals we know today. 
 
 The findings offered a window into 29 regions of the domestic horse's genome that differed from that of the wild Przewalski's horse, suggesting these changes were part of their evolutionary path toward domestication. Some of those changes involved the immune and olfactory systems. 
 
 The analysis also offers hope for the fate of the Przewalski's horse, an endangered animal whose DNA showed no signs of interbreeding with modern horses. 
 
 "It is 100% wild," Willerslev said. "There is no domestic genetics present in that horse. Which of course suggests these guys are really worth preserving." 
 
 The DNA analysis revealed that the species has enough genetic variety to enable it to recover if conservation efforts can be sustained. Once considered extinct in the wild, the horse was reintroduced to the Mongolian steppes in 1985. 
 
 Other scientists who specialize in sequencing ancient DNA praised the work on the Canadian horse. But they cautioned that it wouldn't help them decode the DNA of human ancestors who lived so long ago. 
 
 "We've known for a long time now that DNA preservation is exceptionally good in permafrost compared to other environments," said Mark Stoneking, a geneticist at the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, who was not involved in the study. "Unfortunately, with the exception of Otzi the Iceman, none of our ancestors have been so obliging as to die under circumstances where the remains are frozen soon after death and remain frozen until discovery." 
 
 Paleogeneticist Carles Lalueza-Fox of the Institute of Evolutionary Biology in Barcelona, Spain, who has studied the Neanderthal genome, was also pessimistic: "We are not going to find very ancient humans preserved in permafrost." ||||| During the last ice age, a small horse about the size of a Shetland pony somehow trampled into a big lake. It's unclear how the animal died, but its body fell to the bottom of the lake, where it lay buried for about 16,000 years — that is, until this past fall, when landscapers in Utah unexpectedly unearthed the horse's remains in their backyard. 
 
 The discovery is a rare one. Horses lived in North America from about 50 million to 11,000 years ago, when they went extinct on the continent before being reintroduced by the Europeans thousands of years later, but it's uncommon to find horse remains in Utah, a state that was partly covered by the prehistoric Lake Bonneville. (This ancient lake has since dwindled, forming several smaller lakes, including the Great Salt Lake.) 
 
 It's impossible to know how the horse died, but Rick Hunter, a paleontologist at the Museum of Ancient Life, in Lehi, Utah, who is studying the horse's remains, has several ideas. Perhaps the horse made its way into the lake and then drowned while trying to escape from an ice age predator, such as a short-faced bear or saber-toothed cat, he said. Or maybe the horse died in a stream whose waters emptied into the lake. [10 Extinct Giants That Once Roamed North America] 
 
 "We really don't know for sure," Hunter told Live Science. 
 
 The skull may be missing, but the rest of the horse's body is largely intact. Credit: Thanksgiving Point 
 
 Though the horse's death will remain a mystery, researchers are excited to study its remains. Utah resident Laura Hill and her husband, Bridger Hill, found the skeleton in their yard in September 2017, after landscapers stumbled across it, according to The New York Times. At first, they thought it was a cow skeleton, because Lehi used to be farmland. 
 
 But then, Laura Hill asked her neighbor, a geologist at Brigham Young University, to look at the bones. He suspected the bones belonged to a horse from the Pleistocene, an epoch that lasted from 2.6 million to 11,700 years ago, The New York Times reported. 
 
 Just last week, the Hills told the Museum of Ancient Life about the horse. The bones were a little worse for wear; they'd been exposed to the air for about eight months, children had poked and prodded them, and the landscapers' heavy equipment had destroyed the skull, Hunter said. 
 
 Paleontologists excavate the horse's bones. Credit: Thanksgiving Point 
 
 Even so, it's a prize specimen, he said. Based on the sediment layer where the horse was found, it is likely between 14,000 to 16,000 years old, Hunter said. It's unclear whether the horse was male or female, but it was likely a bit older, given that it had arthritis in its back vertebrae and a bone growth on its right hind leg that looks cancerous, Hunter said. 
 
 A quick examination showed that the horse was short and stocky. Its "femur appears to be as bulky as a modern-day horse, but shorter," Hunter said. 
 
 He noted that the horse's remains aren't fossilized into mineral like some dinosaur bones are. "This animal isn't old enough yet for that to have happened," Hunter said. Rather, the horse's bones stayed moist in the wet ground for thousands of years. When damp, ancient bones are exposed to the dry air, they can dry too quickly and crack. 
 
 To save the bones, researchers can bury them in containers with wet sand and let the water evaporate slowly over several months, Hunter said. 
 
 Paleontologists used a grid to help document the excavation site. Credit: Thanksgiving Point 
 
 "I've seen mammoth bones in the past that have come out of the ground," Hunter said. "Without doing that [wet sand] procedure, they actually just develop really big splits longitudinally down the bone." 
 
 Once the horse's bones are properly preserved, the researchers plan to do more accurate dating on them and determine the species. The Hills still own the horse, because it was found on their land. But the museum is in discussions with them about possibly donating it so that it can go on public display, Hunter said. 
 
 Original article on Live Science.
– Woolly mammoths, saber-toothed tigers, and... horses? According to research using the oldest DNA ever found, horses have been trotting around for millions of years—about 4 million, to be exact. The study, published in Nature, explains how scientists used DNA from a 700,000-year-old horse foot bone found in Canada's Arctic to compare ancient and modern species. What they discovered were exceptional details that dated horse evolution back 2 million years further than previously thought, proving the majestic animals kept some intimidating company. Scientists argue that the bone's discovery in permafrost—which slows DNA decay—has opened doors to how far back they can look. (Before the find, the oldest DNA came from a polar bear that lived more than 110,000 years ago.) It offers "great perspectives as to the level of details we can reconstruct of our origins and the evolutionary history of every animal on the planet," the study lead tells the LA Times. Unfortunately for our own species, says one geneticist, "with the exception of Otzi the Iceman, none of our ancestors have been so obliging as to die under circumstances where the remains are frozen soon after death and remain frozen until discovery."