ANCHORAGE, Alaska — Hundreds of sled dogs and thousands of fans lined up along Anchorage’s Fourth Avenue on March 6 for the ceremonial start of the 1,100-mile Iditarod Trail Sled Dog Race. The dogs leaped and barked when it was their turn to leave the downtown chute for an 11-mile run across Alaska’s largest city. Mushers ran with 12 dogs instead of the 16-dog teams they used when the actual competition started the next day in Willow, about 50 miles to the north. Seventy-one teams were entered in the trek to Nome, an old gold rush town on Alaska’s western coast. More than a third of the mushers are from seven other countries and nine other states. Defending champion Lance Mackey is seeking his fourth consecutive win. The 39-year-old Fairbanks resident, among five past Iditarod winners in this year’s field, signed autographs and posed with fans as he made last-minute checks on his dogs. He said he’s hoping to reach Nome first — if that’s what his dogs are up for.