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Posts Tagged ‘origins of the domestic dog’

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I written about virtually every discovery about ancient dogs.

When I first started writing about this issue, the accepted wisdom was that all dogs had an East Asian origin– largely based upon Peter Savolainen’s extensive mtDNA studies. There was greater mtDNA diversity with East Asian dogs than with those in other parts of the world, and thus, it was deduced that the point of origin had to have been in that part of the world.

In 2009, it was discovered that Sub-Saharan African village dogs also had very similar levels of genetic diversity to East Asia. Dogs are not derived from an population of African wolf, either of the lupaster subspecies or the Ethiopian wolf, and this evidence strongly suggested that the origins of dogs were elsewhere.

In 2010, Robert Wayne’s team at UCLA compared a large sample nuclear DNA from a variety of different breeds and wolves from different parts of the world. Using sophisticate “SNP chip” technology, they were able to compare domestic dogs to extant wolf populations, and they discovered that dogs were most closely related to Middle Eastern wolves. Because of their genetic similarity to Middle Eastern wolves, it was suggested that the Middle East was the point of origin for all dogs.

For the past couple of years, there has been a raging debate about dog origins, which generally fall into two basic camps:  those who back Savolainen’s extensive mtDNA research (which I call East Asia origin theorists) and those who back Robert Wayne’s nuclear research analysis (the Anywhere But East Asia theorists).

To make things even more complicated, the oldest signs of domestication in wolf remains are from neither from East Asia nor the Middle East.  The first of these was a skull that came from Goyet Cave in Belgium. It was a short-skulled wolf, and it dated to 31,700 years ago. Analysis of its mtDNA revealed that its mtDNA, which is inherited matrilineally and thus is not the best DNA to use for tracing origins, was not related to any extant wolf or dog populations. But the shortened skull strongly suggested that this an early dog, not a fully wild wolf.

Then there was the discovery of similar remains in Russia’s Altai Mountains. The Altai Mountains are in Central Asia, and this particular creature’s remains were dated to 33,000 years ago. Most experts thought it was not a dog at all. It was just too old. However, it may have represented an earlier attempt at domestication that then failed as the region’s climate became worse and humans were forced to give up trying to tame animals.

However, in March of this year, it was determined that this animal actually was a dog!  It was closely related to New World dog and modern dog breed but not to any wolves from that region, which means that it had to have come from a different wolf population.

The remains and the DNA studies are in total contradiction with each other.

It is almost impossible to make sense of them all, and the most ambitious attempt to do so is Mark Derr’s How the Dog Became the Dog. All the other books I’ve read on dog origins just ignore data that do not fit whatever postulate is author’s favorite pet theory.

And as if we couldn’t handle one more contradiction, another study was released last week that pointed dog the origins of dogs with ancient European wolves. Analyzing the mtDNA from modern wolves and dogs and from ancient wolves and “dogs” from Eurasia and the New World, the authors found that all dogs were most similar to ancient European wolves.

Wayne, who initially posited that dogs were domesticated in the Middle East, now rejects that finding, claiming that those similarities come from dogs and wolves interbreeding rather extensively in that part of the world.

Wayne speculates rhat the ancestral dogs were derived from a creature he calls the “megafaunal wolf“:

One such wolf, which we call the megafaunal wolf, preyed on large game such as horses, bison and perhaps very young mammoths. Isotope data show that they ate these species, and the dog may have been derived from a wolf similar to these ancient wolves in the late Pleistocene of Europe.

Now, this changes some of my own views on wolf and dog origins. I have postulated that because dogs are mostly Middle Eastern wolves in origin, they are actually “southern type” wolves. Southern type wolves are wolves smaller brains than the big northern wolves everyone knows so well, and some dog breeds actually have larger brains for their body sizes than these wolves do.  I have argued that it might be wrong to say that dogs have had a brain size reduction as a result of domestication.  If they are derived from southern wolves, then some of our dogs may have  actually experienced a brain size increase through domestication, instead of the decrease that is usually discussed when comparing dogs to very large brained northern wolves.

If dogs are derived from this sort of wolf, then they have experienced a brain size reduction, but one still should be careful before positing that  dogs are less intelligent than wolves. Human brains are also smaller than they used to be.

I’m still going to have to think through what this finding means in the grander scheme of dog domestication, but one thing it does suggest is that dogs originated as a type of migratory wolf– a type of migratory wolf that hitched up with another species of migratory hunter.

It utterly debunks the hypothesis that dogs were self-domesticating scavengers from the Neolithic.

Dogs are actually much older than the Neolithic. They were the creations of ancient hunter-gatherer cultures that preyed upon vast herds of ungulates in the taiga and forests of ancient Europe.

They are not inventions of the agricultural era.

Instead, we’ve been at this a while

Human seeing. Canine smelling.

 

 

 

 

 

 

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dingo reflection

The recent discovery that dogs have evolved some adaptations to assist in the digest starches has set off a whole wave of speculation about what this means for the domestication of the species.

Some are thundering about the old Raymond Coppinger theory on dog domestication, which posits that the dog evolved from the wolf during the early days of agriculture. According to this theory, the dog is a self-domesticating animal that evolved solely from wolves losing their fear of humans in order to scavenge from our trash heaps.

The logic here is that starches were only a big part of the human diet only when we began to farm, and if dogs have these adaptations, then it must mean that they were domesticated in agrarian societies.

The problem with this logic is twofold.

The first is that dog remains– which no one argues actually are of dogs–have been dated thousands of years before agriculture. I am thinking of the dog discovered at the Bonn-Oberkassel site and another that was found in the Kesserloch Cave in Switzerland. Both of those remains are 14,000 years old, and they clearly predate agriculture by thousands of years.  In addition to these two dogs, two dogs that were contemporaries of these Central European canines were discovered in Bryansk region of Russia. These two Russian dogs looked a lot like what we’d call mastiffs or mountain dogs.

And never mind that we have several possible dog remains that are even older than these. The Goyet Cave dog of Belgium and the Razboinichya Cave dog of the Altai Mountains are two canid remains that show signs of domestica tion that both date to over 30,000 years ago.

But most amazing of all has been the discovery of 31,500-year-old skulls of what appear to have been dogs in the Czech Republic. These skulls, which were found at the Předmostí, clearly had something to do with people. for one was buried with a bone in its mouth.

All of these discoveries put dog domestication well into the very distant past– long before we had massive trash heaps and long before we ate lots of bread. The dog is the product of wolves tamed during the time of the hunter-gatherers, not of the earliest farmers.

The other problem with claiming that dogs were derived from self-domesticated scavengers is that lots of animals scavenge off of people, including many populations of wolves.

Yet none of these animals– including the wolves– has become more like a dog simply through scavenging. If scavenging was all that it took, then the black-backed jackal would have been the ancestor of the domestic dog. These jackals have been scavenging off of our species long before wolves did, but even though they readily live in villages and often act as guard dogs to warn of the approach of leopards, they show no signs of domestication. There are no spotted or drop-eared black-backed jackals.

And there are no genetically tame raccoons, European badgers, spotted hyenas, or bears.

But all of these animals readily scavenge off our waste.

The only way the Coppinger domestication theory works is to ignore large chunks of science, but that is precisely what so many science journalists do.

The Coppinger theory is a very neat little package that attempts to make simple what was an inordinately complex move.

Almost everything we know about dog domestication is contradictory. We have competing archaeological and genetic evidence, and all that anyone can actually agree on is that the wolf is that the primary ancestor of the dog, the domestication happened before agriculture, and the domestication happened in the Old World.

Mark Derr takes to task some of the speculation that was generated from that study:

By every genetic and archaeological measure, wolves became dogs in the company of hunting and gathering people at least thousands of years before the advent of agriculture. There simply is no way around that.

Derr thinks that humans would have fed wolves cooked grains from wild grasses, which could have accounted for the selection pressures that would have caused dogs to develop the adaptations for consuming starches.

I am a bit skeptical that humans would have been collecting that much grain to feed dogs, but there are cases of hunter-gatherers doing just that. In How the Dog Became the Dog, Derr discusses a study of a site in China. Using isotopic analysis of human and “dog” remains from that site, the researchers found that the humans were growing broomcorn millet to feed both themselves and their dogs.

My bone of contention with this study is that it didn’t include large enough sample of dogs from a variety of breeds. There were no “primitive” breeds included in the study, and there were no dingoes.  Even among the dogs studied, there was variance of how many copies of the amylase-production gene the dog had, which suggests that some dogs are better adapted to a diet rich in grains and starches than others. It would be interesting to see if dogs like dingoes, which lived for thousands of years on a continent with no agriculture, have more copies of the gene than wolves do.

The really interesting part of this study was the discovery that dogs have evolved a tolerance to eating grains and starches.

The unfortunate part of the study is that it caused so much speculation about a theory of dog domestication that is largely contradicted by virtually all the other evidence we have.

In discovering that dogs can eat bread, the researchers threw Raymond Coppinger a bone.

Coppinger is a figure like Lorenz, but unlike Lorenz, who eventually gave up on his hypothesis that most dogs were derived from golden jackals, Coppinger continues to adhere to his self-domestication through neotenic scavenger hypothesis.

Never mind that there are really big holes in the logic behind it.

It is an easy theory to explain between the margins of news copy.

It’s much harder to say that things are much more complex than that.

 

 

 

 

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Let’s say you’ve been asked to identify a tree.

And all you’ve been given are two twigs.

You might get it right.

If you’re educated, you might get within the right genus, but getting the exact species is probably next to impossible.

Now, let’s say someone gave you a log and asked you to do the same thing.

Logs are a bigger part of  the tree.  They have bark, and you can examine the hardness and texture of the wood.

You are much more likely to get it right.

Currently, there is a debate between geneticists about the origin of the domestic dog. One school, which uses studies mtDNA and y-chromosomes, say that dogs have origins in either southern China or Southeast Asia.  The other, which has examined nearly 50,000 SNP’s (single-nucleotide polymorphisms) within the dog genome and found that dogs are most similar in their genome to Middle Eastern wolves.

The ones who are looking at mtDNA and y-chromosomes are looking at twigs.  They are but a tiny fraction of the genome compared to the 50,000 SNP’s.  All mtDNA does is trace maternal heritage, and it’s possible to get severe errors with it, such as under-estimating when savanna and forest elephants split or diving the Indian wolf a separate species.  The exact same errors can be made with y-chromosome analysis. The only difference is that y-chromosome analysis looks at paternal heritage.

That’s why I’m generally dismissive of the new studies (this one and this one) that say dogs are derived from Southeast Asia or East Asian wolves. There are no Southeast Asian wolves, except for a few that live in Myanmar (Burma), so it’s always been a very silly thing for people to puff up about.  Except for those Burmese wolves, there have never been Canis lupus wolves in Southeast Asia, but there have been golden jackals and their relativels. Similarly, Southern China is on on the periphery of the wolf’s range– and always has been.

The landmark study of dog and wolf nuclear DNA was performed at UCLA.  Peter Savolaninen, who is the major proponent of the theory that dog originated in East Asia, complains that this study didn’t include any wolves from south of the Yangtze. It didn’t need to. It included dingoess, which have origins in Southeast Asian domestic dogs. They take the place of that much harder to procure sample.

The problem with these “twig” studies is they are much easier to perform and analyze than the genome-wide analyses.

I’m much more willing to trust a study that used a “log” than one that looked at “twigs.”

***

Mark Derr performs a devastating take-down of the theory that dogs originated in East Asia in How the Dog Became the Dog.  He points out that the time period for which dogs supposedly originated in East Asia does not correspond with any archaeological data. Dogs don’t appear in that part of the world until thousands of years after they appear in other parts of the world.

Now, just because dogs appear to be most closely related to Middle Eastern wolves does not mean that they became morphologically distinct from wolves there.  Derr wrote that the first morphologically distinct dogs would be found in Central Asia– and just a few months later, a 33,000-year-old skull of wolf with domestication features was discovered in the Altai Republic.

It’s also an error to look for an origin time and place for domestic dogs. It actually involved relations between people and wolves that took place over tens of thousands of years.  Middle Eastern wolves were the basis for most dogs we have today, but some of those from East Asia– including the dingo– do show some influence from Chinese wolves. Some European breeds show some influence from European wolves.

 

 

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A great lecture by Robert Wayne on the evolution of domestic dogs and how they came to be so diverse in appearance and genetics.

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From the NY Times:

Borrowing methods developed to study the genetics of human disease, researchers have concluded that dogs were probably first domesticated from wolves somewhere in the Middle East, in contrast to an earlier survey suggesting dogs originated in East Asia.

This finding puts the first known domestication — that of dogs — in the same place as the domestication of plants and other animals, and strengthens the link between the first animal to enter human society and the subsequent invention of agriculture about 10,000 years ago.

A Middle Eastern origin for the dog also fits in better with the archaeological evidence, and has enabled geneticists to reconstruct the entire history of the dog, from the first association between wolves and hunter gatherers some 20,000 years ago to the creation by Victorian dog fanciers of many of today’s breeds.

A research team led by Bridgett M. vonHoldt and Robert K. Wayne of the University of California, Los Angeles, has analyzed a large collection of wolf and dog genomes from around the world. Scanning for similar runs of DNA, the researchers found that the Middle East was where wolf and dog genomes were most similar, although there was another area of overlap between East Asian wolves and dogs. Wolves were probably first domesticated in the Middle East, but after dogs had spread to East Asia there was a crossbreeding that injected more wolf genes into the dog genome, the researchers conclude in Thursday’s issue of the journal Nature.

***

Humans lived as roaming hunters and gatherers for most of their existence. Dr. Wayne believes that wolves began following hunter-gatherer bands to feed on the wounded prey, carcasses or other refuse. At some stage a group of wolves, who happened to be smaller and less threatening than most, developed a dependency on human groups, and may in return have provided a warning system.

Several thousand years later, in the first settled communities that began to appear in the Middle East 15,000 years ago, people began intervening in the breeding patterns of their camp followers, turning them into the first proto-dogs. One of the features they selected was small size, continuing the downsizing of the wolf body plan. “I think a long history such as that would explain how a large carnivore, which can eat you, eventually became stably incorporated in human society,” Dr. Wayne said.

***

Two other experts on dog genetics, Carlos Driscoll and Stephen O’Brien, of the National Cancer Institute, said they believed that Dr. Wayne’s team had made a convincing case. “I think they have nailed the locale of dog domestication to the Middle East,” [emphasis mine] Dr. O’Brien said in an e-mail message from Siberia, where he is attending a tiger management workshop.

Dog domestication and human settlement occurred at the same time, some 15,000 years ago, raising the possibility that dogs may have had a complex impact on the structure of human society. Dogs could have been the sentries that let hunter gatherers settle without fear of surprise attack. They may also have been the first major item of inherited wealth, preceding cattle, and so could have laid the foundations for the gradations of wealth and social hierarchy that differentiated settled groups from the egalitarianism of their hunter-gatherer predecessors. Notions of inheritance and ownership, Dr. Driscoll said, may have been prompted by the first dogs to permeate human society, laying an unexpected track from wolf to wealth.

Well, there goes Peter Savolainen’s theory.

The authors are not dismissive of the Goyet Cave finding. They also don’t put an exact date on domestication.

But what they did do was tear apart Savolainen’s theory that dogs were domesticated 16,000 years ago in southern China. They also find plenty of evidence that dogs and wolves have exchanged genes since the two split into separate “cultures.” Some dogs have similarities East Asian wolf DNA. Others have affinities with European and Middle Eastern wolves. Some even have affinity with North American wolves. The Middle Eastern wolves turned out to be a major influence on domestic dog genetics, which is not all that surprising. This is where people first met Canis lupus.

It was here that the first wolves became curious about their new neighbors.

And the rest is history.


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Tamaskan dog

It is debatable.

That analysis is an excellent summary of what we know right now.

We have a lot of different pieces of evidence that has been discovered through several different disciplines that have used different methodologies.

The problem is that those findings do not fit well with each other at all.

And when you have that sort of situation in science, the whole thing becomes a nasty dog fight of sorts. When you’re dealing with dog  or wolf scientists, these fights seem to take on a whole other level of nasty. (If you want to see what I mean, check out the debates that are in this book. It is really quite fascinating.)

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wolf in zoo

From the NY Times.

Peter Savolainen believes his team has found the origins of the domestic dog in Southern China.

Adam Boyko’s team believes that this conclusion may be premature.

And Stephen O’Brien’s team suggests that there are some holes in the argument that dogs came from East Asia.

And then you have this relatively new study that no one is touching.

And keep in mind that we have actually found the remains of two dogs from the Dnieper Basin that were radio carbon dated to 17,000 years old. I did a post on that finding, but the link to the original abstract has since been taken down. (If someone can find it for me, that would be excellent.)

I think we’re never going to definitively know the origin of the domestic dog. I think that wolf populations have undergone such extreme levels of persecution that whole lines of the species no longer exist. Further, we have had at least one prehistoric subspecies of C. lupus that went extinct after domestic dogs were domesticated.  It is very possible that the subspecies from which domestic dogs descend may have also disappeared.

Dogs are derived from Old World wolves somewhere in Eurasia. It happened a very long time ago– before we had large scale agriculture. That’s what we know for sure.

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red husky blue eye

This post from Archaeozoology lays out what we know about the origin of the domestic dog from the wolf.

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Although I know it bothers some people, I consider domestic dogs conspecific with Canis lupus. However, when I say that, I am not saying that domestic dogs are exactly like the big ungulate hunting wolves we all know from zoos and nature films. Dogs are no more those animals than those animals are Arabian wolves or the extinct shamanu.  However, we regard the wolves of the High Arctic and the wolves of the Northwestern parts of North America as the same species as those little wolves. Each has peculiar adaptations to its environment, and they are different animals. However, they are the same species. I don’t see why it is such a large leap to consider domestic dogs the same species as C. lupus, when we already recognize C. lupus to be a very diverse species in its wild form.

Just as the Arabian wolf is adapted to the hot and arid conditions of the Middle East and the Arctic wolf is adapted to the frigid wastes of the High Arctic, the dog is a wolf that is adapted to live with mercurial hairless apes that produce a lot waste.  It is simply another form of wolf that has adapted to a different environment.

I’ve also thought it a little weird that this reasoning is often mentioned for denying the dog as a subspecies of wolf. Because no wild dogs have reverted to the wolf phenotype and behavior, domestic dogs should be regarded as a separate species. However, feral dogs don’t become wolves, simply because they find scavenging far easier. Wolves and dogs have to learn how to hunt in packs, and if the opportunity never arises, then they never evolve that particular niche.

However, I think this is a bit of a canard. Everyone automatically wants to compare feral dogs with the wolves everyone knows about. Everyone thinks of those big game hunting wolves of northern Eurasia and North America. No one considers the smaller subspecies of wolf, many of which are quite similar to the Australian dingo– which is itself a feral domestic dog that has fully reverted to the wolf behavior and, dare I say, phenotype. The dingo isn’t that much different from the Arabian wolf. It’s not like the wolves of Ellesmere or Isle Royale, but that’s because Australia is more like the Middle East than the cold parts of North America. And there are no moose or caribou to hunt.

Then why do feral domestic dogs in Eurasia and North America retain the dog phenotype? Very simply, feral domestic dogs in those areas are living in an agricultural society.  That means that lots of food can be had without going on hunts or forming packs. And the dogs never evolve the wolf-like behavior or phenotype. It’s just easier to be a lazy dog and scavenge, and this is reflected in their retention of the dog phenotype and behavior.

If people were to disappear, it would not take many generations for domestic dogs to evolve back into wolves or at least wolfish dingo-types. They would evolve back into hunting animals.

So to me, it is Canis lupus familiaris, just as it is Bos primigenius taurus for European-derived domestic cattle and Sus scrofa domestica for domestic pigs.

I don’t know why this tends to launch certain people, but it is very common for domestic animals to be placed as members of the same species to which their wild ancestors belonged.

And no, I’m not saying that wolves should be kept like dogs. Wolves are different in certain respects. However, one can find dogs that act very wolf-like, and one can find wolves that are a docile as domestic dogs, like “Wags.”

I think that the original wolves were much more like “Wags,” because if wolves behaved exactly as they do now, there is absolutely no way that hunter-gatherers could have domesticated them. Domesticating the wolf had to be so easy that a caveman could do it. And that tells me that the ancient wolves probably weren’t the nervous and reactive species that we know today. It was our persecution of the species that selected for these traits in the wolf population, which is why wolves are so hard to keep.

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A new study is challening the theory that domestic dog has East Asian origins.

A new study is challenging the theory that domestic dog has East Asian origins.

Remember that oft-cited study that claims domestic dogs originated in East Asia?

Well, it turns out that the domestic dog’s origins might not be so clear as we once thought.

Peter Savolainen led that study, which compared the genetic diversity of dog populations throughout the world. It turned out in that study that East Asian dogs were more genetically diverse than other populations, and greater genetic diversity is generally associated at the point of origin.

I admit that I always had one reservation about that study. It included our Western breeds, which we all know aren’t that genetically diverse at all. But then I assumed from my reading of the methodology that African and indigenous American dog populations were also not as genetically diverse as the Asian populations.

Well, my assumptions were wrong.

A new study is underway that is challenging Savolainen’s findings.

Dr. Adam Boyko of the Department of Biological Statistics and Computational Biology at Cornell University is leading a new study of dog genetic diversity to see if the origin might be somewhere else. This new study is going to exclude European and Western purebred dogs. This will be a study of the genetic diversity of street dogs.

The early findings showed that African dog populations in Egypt, Uganda, and Namibia were just as genetically diverse as the populations of East Asia.

Now, that blows a hole in the theory that dogs come from East Asian wolves. Why? Because there are no C. lupus wolves in Africa, although there may have been a population of these animals in Libya and Egypt, which may have been absorbed into the golden jackal population. The Ethiopian wolf (C. simensis) is not an ancestor of the domestic dog, although it’s much more closely related to wolves than any species of jackal.

Further, we know that dogs are descended from some sort of Eurasian wolf. We just don’t know which subspecies. So dogs had to have come from Eurasia to Africa. But if they are as genetically diverse in Africa as they are in East Asia, then we simply don’t know where their exact origin is.

The clarity that came from Savolainen’s findings is now muddled.  Boyko’s team will continue to analyze the genetic diversity of dog populations to see if they can find the origin of domestic dogs.

All we know now is that it happened somewhere in Eurasia 15,000 to 40,000 years ago, and that dogs are conspecific with C. lupus.

***

As you might imagine, I’m excited by this finding, because I found this particular study very interesting. Using archeological and paleontological methodology in concert with the DNA analysis, this study found that wolves and dogs were from a very genetically diverse species– I call them ancient wolves to differentiate between modern wolves and domestic dogs–  and that the first anatomically modern dogs were more than 30,000 years old. And what’s more their point of origin was in Europe.

Now, that finding did not square well with the Savolainen study’s findings, but I had not seen any other studies that could point to other origins of the domestic dog. I accepted Savolainen’s study as definitive.

This new Boyko study might be what is necessary to finally figure out where these animals were originally domesticated. And maybe those findings will fit better with what was found from the study remains of dogs and wolves from those European caves.

***

Some of the preliminary findings in the Boyko study are that Rhodesian ridgebacks and Pharaoh hounds are not Africa. The Pharaoh hound finding isn’t new. The historical record and subsequent genetic studies showed a more recent origin for this breed in Malta, where it has been used to hunt rabbits. Now, we know it’s definitely not an African breed.  And I could have told you the Rhodesian ridgeback is not an indigenous African breed. First of all it is mostly comprised European mastiff breeds and sight and scent hounds. The ridge come from pariah dogs that were thought to be indigenous African dogs. However, they were most likely dogs of the Thai ridgeback type that were imported to South Africa by the Portuguese.

Another interesting finding in that Salukis and Afghan hounds share their DNA with Egyptian village dogs. That doesn’t surprise me. Basenjis, which we know are of definite recent African origin, are very closely related to Namibian and Ugandan village dogs.

After all, it was just a few decades ago that the basenji club went to the Congo in search of new blood. In 1990, the AKC even opened up the registry to allow this new African blood into the stud book. It is from this expedition that the brindle basenjis were introduced the bloodline.

***

I can’t wait to see the results of the study.

All we know now is that domestic dogs are derived from some Eurasian wolf population. The finding that all dogs descend from a East Asian wolf ancestor appears to be, if not falsified, at least muddled considerably. And that’s a fascinating preliminary finding.

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