There's been some interesting DNA analysis going on in Japan pertaining to the origin of the extinct Japanese wolves, the Nihon Ken, and dogs in general. This video is in Japanese, but the subtitles are a pretty good translation. They've actually discovered that there was another species of giant wolves in Japan that existed before the 2 known wolf species, Canis Lupus Hattai and Canis Lupus Hodophilax. Enjoy!
Here's a link to an interesting and related paper