Most modern dogs have wolf DNA from relatively recent interbreeding. Here's which breeds are the most and least 'wolfish.'

A black and brown chihuahua on a sidewalk walks toward the camera.

Most modern dog breeds have small amounts of wolf ancestry from long after dogs were domesticated, according to a new study.

The wolf DNA isn't left over from when dogs and wolves diverged; instead, it most likely came from interbreeding in the past few thousand years. That wolfish influence may be linked to certain characteristics, such as size and personality traits, in different dog breeds, researchers reported Nov. 24 in the journal PNAS.