Ancestral breed clustering and composition differences of the sprint and distance Alaskan sled dogs. A). The five ancestral breed clusters signified by distinct colors as determined by Parker et al in 2004, 2007. One hundred forty-one purebred breeds (132 breeds from Parker et al with 9 new breeds) and sprint and distance populations of Alaskan sled dogs are represented in the clusters. Both Alaskan sled dog populations repeatedly cluster among the Ancient/Asian Group (yellow). B). The sprint and distance sled dog populations were investigated for ancestral group composition differences. We observe an increase in the Hunting Group (red) contribution among the sprint dogs and an increase in the Mastiff/Terrier Group (blue) contribution among distance dogs.