According to new studies, what did every modern dog descend from?

Wolves

Explanation: All modern dogs are descendants of wolves, though this domestication may have happened twice, producing groups of dogs descended from two unique common ancestors. ... It was thought until very recently that dogs were wild until about 12,000 years ago.

The dog, Canis familiaris, is a direct descendent of the gray wolf, Canis lupus: In other words, dogs as we know them are domesticated wolves. ... All modern dogs are descendants of wolves, though this domestication may have happened twice, producing groups of dogs descended from two unique common ancestors.