The origin of the domestic dog (Canis lupus familiaris or Canis familiaris) is not clear. Whole genome sequencing indicates that the dog, the gray wolf and the extinct Taymyr wolf diverged at around the same time 27,000–40,000 years ago. These dates imply that the earliest dogs arose in the time of human hunter-gatherers and not agriculturists. Modern dogs are more closely related to ancient wolf fossils that have been found in Europe than they are to modern gray wolves. Nearly all dog breeds' genetic closeness to the gray wolf are due to admixture, except several Arctic dog breeds are close to the Taimyr wolf of North Asia due to admixture.

Modern dogs likely began when human beings were considered to be what?