He and his colleagues studied the genomes of 27 ancient dog bones dug up around the world. Bergström: “To a large degree the history of dogs seems to have been shaped by human history, so likely reflecting how when humans moved they would have brought their dogs with them.”Ancient humans clearly found dogs to be very useful. [Anders Bergström et al, Origins and genetic legacy of prehistoric dogs]One odd finding: about 11,000 years ago it looks like dogs spread more widely than humans did. So how could the dog spread so quickly and widely? The number of copies of a starch-digesting gene in both humans and dogs increased in the generations following the invention of agriculture.