Breed composition of Alaskan sled dogs reflected by three populations based on racing style. The three populations represented extreme sprint, extreme distance, and a 3rd overlapping population of sprint and distance sled dogs. The Alaskan sled dogs are assigned to three populations based on clustering analysis of microsatellite-based markers that are used to establish breed composition of each group. The percentage of each breed is denoted by a different color. The left most group is comprised of ten individuals representative of the "extreme" sprint sled dogs; the right most group is comprised of ten individuals representative of the "extreme" distance sled dogs; and the middle group is comprised of the remaining ten sprint and ten distance sled dogs which cluster together. There is an overall trend for increased Alaskan sled dog, Pointer, and Saluki signature in sprint sled dogs and an increase in Alaskan Malamute and Siberian Husky signature seen in distance sled dogs.