A new study suggests that the close interspecies bond that exists between humans and dogs may extend 27 000 or even 40 000 years back. That's a 1jump from 11 000 to 16 000 years ago, when dogs were 2thought to have split from their wolf ancestors. Led by Harvard research fellow Pontus Skoglun, the authors of the study 3DNA belonging to a 35 000-year-old Siberian wolf specimen. Their genomic analysis led them to 4that the wolf was part of a population "that diverged from the common ancestor of present-day wolves and dogs very close in time to the 5of the domestic dog lineage," according to an abstract. That means domesticated dogs may have been hanging out with humans during that same era, more than 20 000 years ago. The 6for this finding was the discovery of the ancient bone, the abstract notes: The researchers made these 7based on a small piece of bone picked up during an expedition to the Taimyr Peninsula in Siberia. Initially, they didn't realize the bone fragment came from a wolf at all; this was only 8using a genetic test back in the laboratory. But wolves are common on the Taimyr Peninsula, and the bone could have easily 9to a modern-day wolf. On a hunch, the researchers decided to radiocarbon date the bone anyway. It was only then that they realized what they had: a 35 000-year-old bone from an 10Taimyr wolf. A)ancient F)discoveries K)inventions B)appearance G)dramatic L)preview C)belonged H)examined M)previously D)conclude I)impetus N)seldom E)determined J)increasingly O)sudden