Dogs Were Domesticated Twice in Different Locations

The question, 'Where do domestic dogs come from?', has vexed scholars for a very long time. Some argue that humans first domesticated wolves in Europe, while others claim this happened in Central Asia or China. A new paper, published in Science, suggests that all these claims may be right. Supported by funding from the European Research Council and the Natural Environment Research Council, a large international team of scientists compared genetic data with existing archaeological evidence and show that man's best friend may have emerged independently from two separate (possibly now extinct) wolf populations that lived on opposite sides of the Eurasian continent. This means that dogs may have been domesticated not once, as widely believed, but twice.

A major international research project on dog domestication, led by the University of Oxford, has reconstructed the evolutionary history of dogs by first sequencing the genome (at Trinity College Dublin) of a 4,800-year old medium-sized dog from bone excavated at the Neolithic Passage Tomb of Newgrange, Ireland. The team (including French researchers based in Lyon and at the National Museum of Natural History in Paris*) also obtained mitochondrial DNA from 59 ancient dogs living between 14,000 to 3,000 years ago and then compared them with the genetic signatures of more than 2,500 previously studied modern dogs.

The results of their analyses demonstrate a genetic separation between modern dog populations currently living in East Asia and Europe. Curiously, this population split seems to have taken place after the earliest archaeological evidence for dogs in Europe. The new genetic evidence also shows a population turnover in Europe that appears to have mostly replaced the earliest domestic dog population there, which supports the evidence that there was a later arrival of dogs from elsewhere. Lastly, a review of the archaeological record shows that early dogs appear in both the East and West more than 12,000 years ago, but in Central Asia no earlier than 8,000 years ago.

Combined, these new findings suggest that dogs were first domesticated from geographically separated wolf populations on opposite sides of the Eurasian continent. At some point after their domestication, the eastern dogs dispersed with migrating humans into Europe where they mixed with and mostly replaced the earliest European dogs. Most dogs today are a mixture of both Eastern and Western dogs -- one reason why previous genetic studies have been difficult to interpret.

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John Connor's Dog Found

Or is the dog afraid robots will become man's new best friend?

Genetic Evidence Dogs Originated in Central Asia 15,000 Years Ago

Genetic structure in village dogs reveals a Central Asian domestication origin

Authors:

Shannon et al

Abstract:

Dogs were the first domesticated species, originating at least 15,000 y ago from Eurasian gray wolves. Dogs today consist primarily of two specialized groups—a diverse set of nearly 400 pure breeds and a far more populous group of free-ranging animals adapted to a human commensal lifestyle (village dogs). Village dogs are more genetically diverse and geographically widespread than purebred dogs making them vital for unraveling dog population history. Using a semicustom 185,805-marker genotyping array, we conducted a large-scale survey of autosomal, mitochondrial, and Y chromosome diversity in 4,676 purebred dogs from 161 breeds and 549 village dogs from 38 countries. Geographic structure shows both isolation and gene flow have shaped genetic diversity in village dog populations. Some populations (notably those in the Neotropics and the South Pacific) are almost completely derived from European stock, whereas others are clearly admixed between indigenous and European dogs. Importantly, many populations—including those of Vietnam, India, and Egypt—show minimal evidence of European admixture. These populations exhibit a clear gradient of short-range linkage disequilibrium consistent with a Central Asian domestication origin.

Canid Extinction Evidence Competition Does Play an Important Role in Evolution

The role of clade competition in the diversification of North American canids

Authors:

Silvestro et al

Abstract:

The history of biodiversity is characterized by a continual replacement of branches in the tree of life. The rise and demise of these branches (clades) are ultimately determined by changes in speciation and extinction rates, often interpreted as a response to varying abiotic and biotic factors. However, understanding the relative importance of these factors remains a major challenge in evolutionary biology. Here we analyze the rich North American fossil record of the dog family Canidae and of other carnivores to tease apart the roles of competition, body size evolution, and climate change on the sequential replacement of three canid subfamilies (two of which have gone extinct). We develop a novel Bayesian analytic framework to show that competition from multiple carnivore clades successively drove the demise and replacement of the two extinct canid subfamilies by increasing their extinction rates and suppressing their speciation. Competitive effects have likely come from ecologically similar species from both canid and felid clades. These results imply that competition among entire clades, generally considered a rare process, can play a more substantial role than climate change and body size evolution in determining the sequential rise and decline of clades.

Dogs Crossed Into the Americas Only 10,000 Years ago, not With First Waves of Colonists

A new study suggests that dogs may have first successfully migrated to the Americas only about 10,000 years ago, thousands of years after the first human migrants crossed a land bridge from Siberia to North America.

The study looked at the genetic characteristics of 84 individual dogs from more than a dozen sites in North and South America, and is the largest analysis so far of ancient dogs in the Americas. The findings appear in the Journal of Human Evolution.

Unlike their wild wolf predecessors, ancient dogs learned to tolerate human company and generally benefited from the association: They gained access to new food sources, enjoyed the safety of human encampments and, eventually, traveled the world with their two-legged masters. Dogs also were pressed into service as beasts of burden, and sometimes were served as food, particularly on special occasions.

Their 11,000- to 16,000-year association with humans makes dogs a promising subject for the study of ancient human behavior, including migratory behavior, said University of Illinois graduate student Kelsey Witt, who led the new analysis with anthropology professor Ripan Malhi.

"Dogs are one of the earliest organisms to have migrated with humans to every continent, and I think that says a lot about the relationship dogs have had with humans," Witt said. "They can be a powerful tool when you're looking at how human populations have moved around over time."

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Is There Evidence of Paleolithic Domestication of Dogs?

In search of Paleolithic dogs: a quest with mixed results

Author:

Morey

Abstract:

Archaeological evidence has long placed the origins of the domestic dog (Canis lupus familiaris) just prior to the beginning of the Holocene Epoch, some 12,000–15,000 years ago. Some studies of genetic profiles of modern canids have, however, suggested a much earlier origin, dating to Paleolithic times and perhaps exceeding 100,000 years. With such studies as a backdrop, cases have been made recently on archaeological grounds for Paleolithic dogs that in certain cases exceed 30,000 years old. When examined systematically, however, some such studies exhibit conceptual and methodological flaws, calling into serious question the accuracy of the cases advanced. At least one recent study highlights that difficulty. When a series of cases for putative Paleolithic dogs is assessed, convincing cases for such dogs are confined to about the past 15,000 years, or latest Paleolithic times. Further developments on certain specific fronts may change that, but for the time being the longstanding archaeological understanding of the dog domestication time frame continues to be reasonably accurate. Recent molecular genetic studies are converging on that temporal framework as well. Archaeologists need not be automatically swayed by ongoing changes in molecular genetic profiles.

Was Man's Best Friend Key to the Sixth Mass Extinction?

A new analysis of European archaeological sites containing large numbers of dead mammoths and dwellings built with mammoth bones has led Penn State Professor Emerita Pat Shipman to formulate a new interpretation of how these sites were formed. She suggests that their abrupt appearance may have been due to early modern humans working with the earliest domestic dogs to kill the now-extinct mammoth -- a now-extinct animal distantly related to the modern-day elephant. Shipman's analysis also provides a way to test the predictions of her new hypothesis. Advance publication of her article "How do you kill 86 mammoths?" is available online through Quaternary International.

Spectacular archaeological sites yielding stone tools and extraordinary numbers of dead mammoths -- some containing the remains of hundreds of individuals -- suddenly became common in central and eastern Eurasia between about 45,000 and 15,000 years ago, although mammoths previously had been hunted by humans and their extinct relatives and ancestors for at least a million years. Some of these mysterious sites have huts built of mammoth bones in complex, geometric patterns as well as piles of butchered mammoth bones.

"One of the greatest puzzles about these sites is how such large numbers of mammoths could have been killed with the weapons available during that time," Shipman said. Many earlier studies of the age distribution of the mammoths at these sites found similarities with modern elephants killed by hunting or natural disasters, but Shipman's new analysis of the earlier studies found that they lacked the statistical evaluations necessary for concluding with any certainty how these animals were killed.

Surprisingly, Shipman said, she found that "few of the mortality patterns from these mammoth deaths matched either those from natural deaths among modern elephants killed by droughts or by culling operations with modern weapons that kill entire family herds of modern elephants at once." This discovery suggested to Shipman that a successful new technique for killing such large animals had been developed and its repeated use over time could explain the mysterious, massive collections of mammoth bones in Europe.

The key to Shipman's new hypothesis is recent work by a team led by Mietje Germonpré of the Royal Belgian Institute of Natural Sciences, which has uncovered evidence that some of the large carnivores at these sites were early domesticated dogs, not wolves as generally had been assumed. Then, with this evidence as a clue, Shipman used information about how humans hunt with dogs to formulate a series of testable predictions about these mammoth sites.

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Genetic Evidence Dogs Were Domesticated in Europe First

Wolves likely were domesticated by European hunter–gatherers more than 18,000 years ago and gradually evolved into dogs that became household pets, UCLA life scientists report.

"We found that instead of recent wolves being closest to domestic dogs, ancient European wolves were directly related to them," said Robert Wayne, a professor of ecology and evolutionary biology in UCLA's College of Letters and Science and senior author of the research. "This brings the genetic record into agreement with the archaeological record. Europe is where the oldest dogs are found."

[...]

For the current study in Science, the researchers studied 10 ancient "wolf-like" animals and eight "dog-like" animals, mostly from Europe. These animals were all more than 1,000 years old, most were thousands of years old, and two were more than 30,000 years old.

The biologists studied the mitochondrial DNA of the animals, which is abundant in ancient remains. (Mitochondria are tiny sub-cellular structures with their own small genome.) By comparing this ancient mitochondrial DNA with the modern mitochondrial genomes of 77 domestic dogs, 49 wolves and four coyotes, the researchers determined that the domestic dogs were genetically grouped with ancient wolves or dogs from Europe — not with wolves found anywhere else in the world or even with modern European wolves. Dogs, they concluded, derived from ancient wolves that inhabited Europe and are now extinct.

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Parallel Evolution Between Dogs and Hyenas

Falkland Islands Wolf Mystery Solved

University of Adelaide researchers have found the answer to one of natural history's most intriguing puzzles – the origins of the now extinct Falkland Islands wolf and how it came to be the only land-based mammal on the isolated islands – 460km from the nearest land, Argentina.

Previous theories have suggested the wolf somehow rafted on ice or vegetation, crossed via a now-submerged land bridge or was even semi-domesticated and transported by early South American humans.

The 320-year-old mystery was first recorded by early British explorers in 1690 and raised again by Charles Darwin following his encounter with the famously tame species on his Beagle voyage in 1834.

Researchers from the University's Australian Centre for Ancient DNA (ACAD) extracted tiny pieces of tissue from the skull of a specimen collected personally by Darwin. They also used samples from a previously unknown specimen, which was recently re-discovered as a stuffed exhibit in the attic of Otago Museum in New Zealand.

The findings were published in Nature Communications today and concluded that, unlike earlier theories, the Falkland Islands wolf (Dusicyon australis) only became isolated about 16,000 years ago around the peak of the last glacial period.

"Previous studies used ancient DNA from museum specimens to suggest that the Falkland Islands wolf diverged genetically from its closest living relative, the South American maned wolf (Chrysocyon brachyurus) around seven million years ago. As a result, they estimated that the wolf colonised the islands about 330,000 years ago by unknown means," says Associate Professor Jeremy Austin, Deputy Director of ACAD and co-lead author with Dr Julien Soubrier.

"Critically, however, these early studies hadn't included an extinct relative from the mainland, the fox-like Dusicyon avus. We extracted ancient DNA from six specimens of D. avus collected across Argentina and Chile, and made comparisons with a wide group of extinct and living species in the same family."

ACAD's analyses showed that D. avus was the closest relative of the Falkland Islands wolf and they separated only 16,000 years ago – but the question of how the island colonisation came about remained. The absence of other mammals argued against any land bridge connection to the mainland.

"The Eureka moment was finding evidence of submarine terraces off the coast of Argentina," says study leader Professor Alan Cooper. "They recorded the dramatically lowered sea levels during the Last Glacial Maximum (around 25-18,000 years ago)."

"At that time, there was a shallow and narrow (around 20km) strait between the islands and the mainland, allowing the Falkland Islands wolf to cross when the sea was frozen over, probably while pursuing marine prey like seals or penguins. Other small mammals like rats weren't able to cross the ice."

I Didn't Realize...

I am reading Dogs: Their Fossil Relatives and Evolutionary History. I'm about 3/4 done.

I just didn't realize that they were almost strictly a North American lineage that had been restricted to our continent until extremely recently.

Hmmm.

*hand waves*


No dogs in the Old World. Or rather there was a single species that goes over to the Old World and it doesn't do well for whatever reason and is extinct by the time humanity is ready to domesticate (sorta the reverse of what happened with the Hyena lineage in OTL. However, dogs are present in the New World.

Would there be a replacement for the canids domestically? Could there be? Cats aren't dogs and cheetahs are about the closest thing that a big cat can produce that would domesticate well, except they just gotta run for their courtships to be successful...Most other cats are just not social enough, too.

A bear line then? hmmm.

What do others think?

Just what was filling the dog niche in the Old World prior to canids? Hyenas?