Another new research report, this time by
Peter Savolainen and colleagues, asserts that dogs were first domesticated in East Asia.
Their work too was based on work comparing dog and wolf genes from around the world.
A former graduate student in Wayne's UCLA lab, Jennifer A.
Leonard, extracted DNA from bones of dogs from archaeological sites in Peru, Bolivia and
Mexico. She then compared the DNA with DNA from modern dogs and modern wolves.
Much of the DNA was well preserved, said Leonard, currently a postdoctoral fellow at
the Smithsonian Institution's National Museum of Natural History in Washington, D.C.
|"Our results show that
ancient American dogs were more similar to dogs from the Old World than to gray wolves of
North America," Leonard said. "This implies that when nomadic hunter-gatherers
migrated across the Bering Strait from Asia into North America, at least
12,00014,000 years ago, they already had dogs with them. The diversity observed in
the ancient American dogs indicates that multiple lineages of dogs were taken in to the
hunter-gatherers brought the dogs enormous distances, which shows that the dogs were
regarded as very valuable.
"Dogs are expensive traveling
companions, who require food and care," said Wayne, a co-author of the research.
"They must have served an important function in ancient societies, and have been
thoroughly domesticated to move great distances without wandering off into the
countryside. We believe they were a fundamental part of ancient societies. Dogs may have
been valued for their hunting skills, security, transport, warmth, perhaps even helping
early travelers to move great distances.
"Dogs are the only domesticated animal
that had a New World and Old World distribution before the arrival of Columbus to North
America," Wayne said.
What characteristics of dogs caused them to have such high
value in ancient societies and why were they domesticated thousands of years before other
animals and plants? 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, Wayne said.
"Did dogs contribute to the rapid
expansion of humans into the New World?" Wayne asked. "At this point we can only
speculate about the way dogs changed early human societies, but our new findings suggest
that the effect may have been profound."
When did the association between humans and
dogs begin? By the time humans arrived in the New World, the diversity of dogs was already
substantial and dogs were spread across Eurasia, Wayne said.
"This suggests a very long coexistence
of humans and dogs," Wayne said. "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."
|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 counterparts.
"Consequently, these data suggest Native American dogs have not
genetically contributed to modern dog breeds," Wayne said. "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."
Dogs in Antiquity: Anubis to Cerberus:
the Origins of
the Domestic Dog
The new molecular genetic analysis
suggests that the majority of the living dog gene pool does not contain any ancestry from
these long isolated Native American dogs, Wayne said.
"This implies selective breeding, either
intentional where European colonists forcefully discouraged the breeding of native
dogs, as they did with other aspects of native culture or dogs of European origin
may simply have been considered more desirable; both scenarios may have occurred in
different regions. There was not wide-scale interbreeding of European and native American
dogs; native American breeds did not persist into the modern dog gene pool."
The scientists on the study also include
evolutionary biologist Carles Vila from Uppsala University, Sweden, and zooarchaeologists
from Mexico and Peru: Jane Wheeler, Raul Valadez and Sonia Guillen. Wayne's research
was partially funded by the National Science Foundation.
Meanwhile, Peter Savolainen and colleagues found
greater diversity of genetic types among the dogs in China, Thailand, Cambodia, Tibet,
Korea and Japan than among the dogs in Europe, West Asia, Africa and Arctic America.
Finding greater genetic diversity -- essentially more unique types of dogs -- in a
region typically means greater age for a species or population in that area of the world.
It was this that led the research team to conclude that dogs were first
domesticated from Asian wolves, perhaps from several females in one wolf population.
"It is more probable that all the modern
types have come from East Asia to Europe than other way around," Savolainen, an
evolutionary biologist at the Royal Institute of Technology in Stockholm, Sweden, told
Nature Science Update.
To Learn More: [ Top ]
· BBC: Origins of Dog
Date: November 22, 2002 | By Christine McGourty
· China Daily: Origin
of Dogs Traced to China
Date: November 27, 2002
News Network: Scientists Trace the Origins of Dogs, with
images of Mexican Hairless and Husky that share Old World genes
Date: November 22, 2002 | By
· UCLA News
Release: Humans Brought Domestic Dogs to New World
Date: December 2, 2002 | Contact: Stuart Wolpert,
· New York Times -
Abstract: "From Wolf to Dog - Yes But When?"
Date: November 22, 2002 | By Nicholas Wade
Article at WDW: Dogs May Date Back 100,000 Years
1997 Science Article on Dog Origins
THIS BOOK: Dogs: A
Startling New Understanding of Canine Origin, Behavior &
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READ: A Review of Ray & Lorna Coppinger's
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READ: An Interview with Ray & Lorna
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LINKS: Try the following for more
· Molecular Evolution of
the Dog Family
· The Multiple and
Ancient Origins of the Domestic Dog
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