Analysis of the Mitochondrial Genomes of Japanese Wolf Specimens in the Siebold Collection, Leiden.

The taxonomic status of extinct Japanese or Honshu wolves (Canis lupus hodophilax) has been disputed since the name hodophilax was first proposed by Temminck in 1839 on the basis of specimens stored in Leiden, the Netherlands. Points of controversy include whether the type specimen of hodophilax (Jentink c: RMNH.MAM.39181) and the other two specimens from Leiden (Jentink a: RMNH.MAM.39182 and Jentink b: RMNH.MAM.39183) represent different varieties or subspecies of Japanese wolves or not. Two Japanese names, ookami and jamainu, used to describe wild Canis species, further complicate the issue. In this study, the taxonomic status of Japanese wolves was clarified using mitochondrial DNA of the three specimens stored at the Naturalis Biodiversity Center in Leiden, in addition to three Japanese wolf specimens stored at the Museum für Naturkunde in Berlin and five new samples from Japan. The mitochondrial genomes of the type specimen of hodophilax (Jentink c) and another sample from Leiden (Jentink b) as well as Berlin specimens were included in the cluster of Japanese wolves distinct from other grey wolves. However, the other sample from Leiden (Jentink a) was identified as a domestic dog. A mitochondrial genome analysis suggested that Japanese wolves could be categorized into two distinct clusters. Studies of nuclear genomes are needed to further clarify the taxonomic status, divergence time, and population genetic structure of Japanese wolves.

Japanese Wolves are Genetically Divided into Two Groups Based on an 8-Nucleotide Insertion/Deletion within the mtDNA Control Region.

The mitochondrial DNA (mtDNA) control region (198- to 598-bp) of four ancient Canis specimens (two Canis mandibles, a cranium, and a first phalanx) was examined, and each specimen was genetically identified as Japanese wolf. Two unique nucleotide substitutions, the 78-C insertion and the 482-G deletion, both of which are specific for Japanese wolf, were observed in each sample. Based on the mtDNA sequences analyzed, these four specimens and 10 additional Japanese wolf samples could be classified into two groups- Group A (10 samples) and Group B (4 samples)-which contain or lack an 8-bp insertion/deletion (indel), respectively. Interestingly, three dogs (Akita-b, Kishu 25, and S-husky 102) that each contained Japanese wolf-specific features were also classified into Group A or B based on the 8-bp indel. To determine the origin or ancestor of the Japanese wolf, mtDNA control regions of ancient continental Canis specimens were examined; 84 specimens were from Russia, and 29 were from China. However, none of these 113 specimens contained Japanese wolf-specific sequences. Moreover, none of 426 Japanese modern hunting dogs examined contained these Japanese wolf-specific mtDNA sequences. The mtDNA control region sequences of Groups A and B appeared to be unique to grey wolf and dog populations.