Evolution of wolf into dog

The evolution of the wolf occurred over a geologic time scale of 800 thousand years, transforming the first wolf specimen that is recognized as being morphologically similar to Canis lupus into today's dog, dingo and gray wolf. Ecological factors including habitat type, climate, prey specialization and predatory competition has greatly influenced the wolf's genetic population structure and cranio-dental plasticity. Wolves went through a population bottleneck 20,000 years before present (YBP), which indicates that many wolf populations had gone extinct at a time that coincided with the Last Glacial Maximum and the expansion of modern humans worldwide with their technology for capturing large game. The domestic dog is the most widely abundant large carnivore and a descendant from one of those now-extinct wolf populations. Today, the wolf is represented by the many extant subspecies of Canis lupus, which includes the dog and dingo.

The fossil record for ancient vertebrates is composed of rarely occurring fragments from which it is often impossible to obtain genetic material. Researchers are limited to morphologic analysis but it is difficult to estimate the intra-species and inter-species variations and relationships that existed between specimens across time and place. Some observations are debated by researchers who do not always agree, and hypotheses that are supported by some authors are challenged by others.

There is general agreement on the most ancient record, which shows that feliforms and caniforms emerged within the super-family Carnivoramorpha 43 million years before present (YBP). The caniforms included the fox-like genus whose various species existed from 34 million YBP before branching 11.9 million YBP into Vulpes (foxes) and Canini (canines). The jackal-sized Eucyon existed in North America from 10 million YBP and by the Early Pliocene about 6–5 million YBP the coyote-like Eucyon davisi invaded Eurasia. In North America it gave rise to early Canis which first appeared in the Miocene (6 million YBP) in south-western US and Mexico. By 5 million YBP the larger Canis lepophagus appeared in the same region.

...
Wikipedia