Origin of the domestic dog matched across Eurasia and its branch is phylogenetically rooted in the same sequence as the Altai dog (not a direct ancestor). The subclade d2 hybrid haplotypes are found in 2.6% of South-West Asian dogs. Haplogroup E: Derived from post-domestication wolf–dog hybridization in East Asia, (rare distribution in South-East Asia, Korea and Japan). Haplogroup F: Derived from post-domestication wolf–dog hybridization in Japan. A study of 600 dog specimens found only one dog whose sequence indicated hybridization with the extinct Japanese wolf. It is not known whether this hybridization was the result of humans selecting for phenotypic traits from local wolf populations
Origin of the domestic dog connected to the mainland at that time. The dogs were selectively bred as either sled dogs or as hunting dogs, which implies that a sled dog standard and a hunting dog standard existed at that time. The optimal maximum size for a sled dog is 20–25 kg based on thermo-regulation, and the ancient sled dogs were between 16–25 kg. The same standard has been found in the remains of sled dogs from this region 2,000 YBP and in the modern Siberian husky breed standard. Other dogs were more massive at 30 kg and appear to be dogs that had been