DNA study suggests dog evolution 'earlier than thought'
22 May 2015 Last updated at 06:41 BST
Dogs may have been domesticated much earlier than previously though, Swedish researchers have suggested.
A genetic study indicates that dogs may have begun to split from wolves 27,000 years ago.
The study, outlined in Current Biology, might also explain the deep bond between dogs and humans.
Science correspondent Pallab Ghosh reports.