---

---

---

---

Science Current Events and Science News RSS Feeds

---

---

Email a Friend Printer Friendly

Old World Origin of New World Dogs

November 22, 2002

When humans arrived to the New World they had dogs with them. This is the conclusion reached by a study published this week in the journal Science by evolutionary biologists at the University of California, Los Angeles, and Uppsala University, Sweden, in collaboration with zooarchaeologists from Mexico and Peru.

Dogs have been present in the New World for a very long time. Archaeological remains suggest that they were in North America at least 9,000 to 10,000 years ago. They were the only domesticated species to have an Old and New World distribution before the arrival of Columbus to North America. Dogs were domesticated from gray wolves and therefore, a logical explanation for this long presence in the New World is that they were independently domesticated from gray wolves in North America by native Americans. To test this hypothesis, the researchers studied the mitochondrial DNA from ancient bones of dogs from different areas across Latin America and Alaska that were deposited before the arrival of Europeans colonists and conquistadors. The results showed that ancient American dogs were more similar to dogs from the Old World than to gray wolves of North America. This implies that when nomadic hunter-gatherers migrated across the Bering Strait from Asia into North America, at least 12-14,000 years ago, they already had dogs with them. Additionally, the diversity observed in the ancient American dogs indicates that multiple lineages of dogs were taken into the New World.

        The study suggests that at a time when small, nomadic hunter-gatherer groups predominated and trade was limited, dogs were nonetheless a common feature in human settlements separated by more than 9,000 km, from Europe to America. What characteristics of dogs caused them to have such high value in ancient societies and why were they domesticated thousands of years before other plants and animals? The answers to these questions are obscured by the long unwritten history of dogs and by the dramatic difference between the role of dogs in ancient and modern societies. Did dogs contribute to the rapid expansion of humans into the New World? At this point we can only speculate about the way dogs changed early human societies, but these new findings suggest that the effect may have been profound.

        When did the association between humans and dogs begin? By the time humans arrived to the New World the diversity of dogs was already substantial and they were spread over three continents at least. This suggests a very long coexistence of humans and dogs. Previous genetic analyses support this conclusion and have suggested that this association could have lasted tens of thousands of years. Dogs have been living in close association with humans much longer than any other domestic animal or plant species.

Modern and old American dogs are different
Although New and Old World dogs are descended from the same Old World wolf ancestor, the DNA sequences from ancient American dogs are slightly different from their modern conspecifics. Consequently, these data suggest Native American dogs have not genetically contributed to modern dog breeds. DNA sequences from hundreds of dogs from dozens of modern breeds from throughout the world do not show traces of American ancestry. Native dogs may still have living descendants in some unsampled New World population but their absence for a large sample of modern dogs reinforces the dramatic impact that the arrival of Europeans had on native cultures

Jennnifer A.Leonard, Robert K. Wayne, Jane Wheeler, Ra'ºl Valadez, Sonia Guillen, Carles Vil'¡, Ancient DNA Evidence for Old World Origin of New World Dogs, Science, November 22 2002.

Vetenskapsrådet (The Swedish Research Council)