 The phylogenetic tree generated from its mitochondrial DNA sequences revealed a long branch that separated the Japanese wolf from other gray wolf populations and that it belongs to the ancient mDNA haplogroup 2 (represented today by the Italian wolf and scattered pockets of other wolves across Eurasia), while the Hokkaido wolf belongs to mDNA haplogroup 1 and this suggests that the Japanese wolf was the first arrival on the Japanese archipelago with the Hokkaido wolf arriving more recently from the north.The wolf was estimated to have arrived in Japan during the Late Pleistocene between 25,000–125,000 years ago, however a more recent study that looked at the past sea levels of the Korean Strait together with the timing of the Japanese wolf sequences indicated that it arrived to the southern islands less than 20,000 YBP.An examination of sequences from 113 ancient "Canis" specimens from China and Russia did not match, which indicated that none of these specimens were the ancestors of the Japanese wolf.