Origin of the domestic dog or the result of natural introgression as the dog expanded across Eurasia. In 2018, a study found a small amount of dog ancestry in 62% of Eurasian wolf specimens looked at, that hybridization had occurred across a wide number of timescales and not just recently, however in contrast there was almost no admixture detected in the North American specimens. There was introgression of the male dog into the wolf, but also one hybrid detected which was the result of a male wolf crossed with a female dog. Wolves have maintained their phenotype differences from the dog, which indicates low-frequency hybridization.
Origin of the domestic dog result of a female wolf/male dog pairing. Haplogroup A: Includes 64-65% of dogs. Haplotypes of subclades a2–a6 are derived from post-domestication wolf–dog hybridization. Haplogroup B: Includes 22-23% of dogs. haplotypes of subclade b2 are derived from post-domestication wolf–dog hybridization. Haplogroup C: Includes 10-12% of dogs. Haplogroup D: Derived from post-domestication wolf–dog hybridization in subclade d1 (Scandinavia) and d2 (South-West Asia). The northern Scandinavian subclade d1 hybrid haplotypes originated 480-3,000 YBP and are found in all Sami-related breeds: Finnish Lapphund, Swedish Lapphund, Lapponian Herder, Jamthund, Norwegian Elkhound and Hällefors Elkhound. The maternal wolf sequence that contributed to them has not been