By Kerry Tasker and Steve Gorman ANCHORAGE, Alaska (Reuters) – The world’s most famous sled-dog race gets under way on Saturday when 38 mushers and their canine teams, one of the smallest rosters of competitors ever, line up in downtown Anchorage, Alaska, to start the 52nd annual running of the Iditarod. The untimed and ceremonial 11-mile (18 km) jaunt through the state’s most populous…