Tag: Dr George Johnson

Origins of the Dog, a repeat!

Dogs and humans go back a very long way.

I wrote in my post of the 23rd: “In fact tomorrow I shall republish a post I wrote in 2015 about the origins of the dog!

Well tomorrow wasn’t possible with the sad news of the loss of our cat.

But it is today! It was originally published on the 13th July, 2015 – my how 5 years have sped by!

So here it is again. I suspect many of you have not read it!

ooOOoo

The Origins of the Dog.

Dogs and humans go back even further than previously thought.

Humans and dogs were constant companions well before our ancestors settled in villages and started growing crops 10,000 years ago

I have no doubt that thousands of dog owners all around the world must be enthralled by the way that dogs relate to us and, in turn, how we humans relate to dogs. More than once a day, one of our dogs will do something that has me and Jean marvelling at their way of living so close to us.

Then when one starts to reflect on how long dogs and humans have been together, perhaps it could be seen as the direct result of that length of relationship.

Now there’s nothing new in me writing this, after all the home page of Learning from Dogs states:

Yet they have been part of man’s world for an unimaginable time, at least 30,000 years. That makes the domesticated dog the longest animal companion to man, by far!

Back in May the website Livescience published an article that revealed more about the length of our relationship with dogs. This is how it opened:

Ancient Wolf DNA Could Solve Dog Origin Mystery

by Becky Oskin, Senior Writer

Humans and dogs were constant companions well before our ancestors settled in villages and started growing crops 10,000 years ago, a new study suggests.

Genetic evidence from an ancient wolf bone discovered lying on the tundra in Siberia’s Taimyr Peninsula reveals that wolves and dogs split from their common ancestor at least 27,000 years ago. “Although separation isn’t the same as domestication, this opens up the possibility that domestication occurred much earlier than we thought before,” said lead study author Pontus Skoglund, who studies ancient DNA at Harvard Medical School and the Broad Institute in Massachusetts. Previously, scientists had pegged the wolf-dog split at no earlier than 16,000 years ago.

The Livescience article referred to results that were published in the journal Current Biology on May 21st this year. One needs a subscription to read the full report but here is their summary:

The origin of domestic dogs is poorly understood [ 1–15 ], with suggested evidence of dog-like features in fossils that predate the Last Glacial Maximum [ 6, 9, 10, 14, 16 ] conflicting with genetic estimates of a more recent divergence between dogs and worldwide wolf populations [ 13, 15, 17–19 ]. Here, we present a draft genome sequence from a 35,000-year-old wolf from the Taimyr Peninsula in northern Siberia. We find that this individual belonged to a population that diverged from the common ancestor of present-day wolves and dogs very close in time to the appearance of the domestic dog lineage. We use the directly dated ancient wolf genome to recalibrate the molecular timescale of wolves and dogs and find that the mutation rate is substantially slower than assumed by most previous studies, suggesting that the ancestors of dogs were separated from present-day wolves before the Last Glacial Maximum. We also find evidence of introgression from the archaic Taimyr wolf lineage into present-day dog breeds from northeast Siberia and Greenland, contributing between 1.4% and 27.3% of their ancestry. This demonstrates that the ancestry of present-day dogs is derived from multiple regional wolf populations.

That summary page also includes the following Graphical Abstract:

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I don’t have permission to republish the Livescience article in full but would like to offer the closing paragraphs of this fascinating report.

“It is a very well-done paper,” Perry [George Perry, an expert in ancient DNA at Pennsylvania State University] told Live Science. “This topic is a critical one for our understanding of human evolution and human-environment interactions in the Paleolithic. Partnership with early dogs may have facilitated more efficient hunting strategies.”

If dogs first befriended hunter-gatherers, rather than farmers, then perhaps the animals helped with hunting or keeping other carnivores away. For instance, an author of a new book claims humans and dogs teamed up to drive Neanderthals to extinction. Skoglund also suggested the Siberian husky followed nomads across the Bering Land Bridge, picking up wolf DNA along the way.

“It might have been beneficial for them to absorb genes that were adapted to this high Arctic environment,” Skoglund said.

This is the first wolf genome from the Pleistocene, and more ancient DNA from prehistoric fossils could provide further insights into the relationship between wolves, dogs and humans, the researchers said.

Yes, our dogs have been part of man’s world for an unimaginable time – and Jean and I, as with tens of thousands of others, can’t imagine a world without dogs.

ooOOoo

They are our supreme companions. They don’t judge. They don’t lie. They are …. well let me repeat what I wrote right at the beginning of the blog.

Dogs are part of the Canidae, a family including wolves, coyotes and foxes, thought to have evolved 60 million years ago.  There is no hard evidence about when dogs and man came together but dogs were certainly around when man developed speech and set out from Africa, about 50,000 years ago.  See an interesting article by Dr. George Johnson.

Because of this closeness between dogs and man, we (as in man!) have the ability to observe the way they live.  Now I’m sure that scientists would cringe with the idea that the way that a dog lives his life sets an example for us humans, well cringe in the scientific sense.  But man seems to be at one of those defining stages in mankind’s evolution where the forces bearing down on the species homo sapiens have the potential to cause very great harm.  If the example of dogs can provide a beacon of hope, an incentive to change at a deep cultural level, then the quicker we ‘get the message’, the better it will be.

Dogs:

  • are integrous ( a score of 210) according to Dr David Hawkins
  • don’t cheat or lie
  • don’t have hidden agendas
  • are loyal and faithful
  • forgive
  • love unconditionally
  • value and cherish the ‘present’ in a way that humans can only dream of achieving
  • are, by eons of time, a more successful species than man.

There! Nothing more to say!

Evolution of the family dog.

A republication of an essay on the history of dogs.

Dr. George Johnson
Dr. George Johnson

For some time I have been aware of an essay authored by Dr. George Johnson under his On Science series page umbrella.  As that page explains:

ON SCIENCE is a weekly science column written by me (George Johnson), published initially in the St. Louis Post Dispatch, and now in the online newspaper St. Louis Beacon (stlbeacon.org). For over 30 years I taught biology to college students at Washington University. For the last decade of these years, I taught a freshman course that introduced nonscience majors to current issues where science plays a key role, issues such as AIDS, the environment, cloning, genetic engineering, and evolution.

The course was intended to give them the tools to think about these issues as citizens and voters. I write my column as a way of teaching the general public about these same issues.

Most people are very interested in science, but put off by the terminology. When you don’t know what the words mean, it’s easy to slip into thinking that the matter is difficult, when actually the ideas are simple, easy to grasp, and fun to consider. It’s the terms that get in the way, that stand as a wall between citizens and science.

It is the intent of my column to turn those walls into windows, so that readers can peer in and join the fun. Analogies are my tool. In each column I look for simple analogies that relate the matter at hand to things we all know. As science, analogies are not exact, but I do not count myself compromised. Analogies trade precision for clarity. If I do my job right, the key idea is not compromised by the analogy I use to explain it, but rather revealed.

A quick trip to Dr. Johnson’s bio details reveals a substantial academic background.

Anyway, the particular essay that I was very interested in was, unsurprisingly, one about the history of the domestic dog.

I wrote Dr. Johnson asking for permission to publish his essay here on Learning from Dogs and promptly received such permission.  Indeed, better than that, here is his reply email:

By all means, but please cite a revised version of the article (in ESSENTIALS OF THE LIVING WORLD, 5e, George B Johnson, McGraw Hill Publ., 2015). It is somewhat shorter, but more up-to-date. I enclose a copy of the relevant page below.

Enjoy!

Screen Shot 2014-07-14 at 9.49.36 AM

What is the dog?

Time to attempt an answer to this fundamental, well for this Blog, question!

 

Like wolves, the Dingo is smarter than pet dogs.

(The above photograph comes from an article on ImpactLab – see foot of Post for more details.)

When putting together the Blog ahead of the publication of the very first Post on July 15th, 2009, some 820 Posts ago, I prepared some additional material that set out to justify the Raison d’être for the venture.  Included was a piece regarding Dogs and integrity.  There I wrote:

Dogs are part of the Canidae, a family including wolves, coyotes and foxes, thought to have evolved 60 million years ago.  There is no hard evidence about when dogs and man came together but dogs were certainly around when man developed speech and set out from Africa, about 50,000 years ago.  See an interesting article by Dr. George Johnson.

Anyway, I revisited the article written by Dr Johnson and thought it worthy of being published in full, as a separate article in Learning from Dogs.  I requested permission to reproduce the article in full and Dr. George Johnson was very gracious in quickly coming back to me giving his agreement.  Thank you.  The original article can be read here, the ONSCIENCE home page is here and Dr. Johnson’s details are here.

Evolution of the family dog

I first suspected that Boswell would have a short life when he bit my wife on our nuptial bed.

Boswell was my dog, a feisty Toto-like terrier who shared my bachelor bed and resented the intrusion of a woman where he felt a dog — Boswell — ought to be. As it turns out, my suspicion was correct, and he did not live out the year, which was 1982. Staying with others while I and my bride were overseas, Boswell resented being denied chicken bones, ate them anyway, and died of the consequences. To this day I miss him.

This week I found myself wondering about Boswell’s origins. From what creature did the domestic dog arise? Darwin suggested that wolves, coyotes, and jackals — all of which can interbreed and produce fertile offspring– may all have played a role, producing a complex dog ancestry that would be impossible to unravel. In the 1950s, Nobel Prize-winning behaviorist Konrad Lorenz suggested some dog breeds derive from jackals, others from wolves.

Based on anatomy, most biologists have put their money on the wolf, but until recently there was little hard evidence, and, as you might expect if you know scientists, lots of opinions.

The issue was finally settled in 1997 by an international team of scientists led by Robert Wayne of the University of California, Los Angeles. To sort out the evolutionary origin of the family dog, Wayne and his colleagues used the techniques of molecular biology to compare the genes of dogs with those of wolves, coyotes and jackals.

Wayne’s team collected blood, tissue, or hair from 140 dogs of sixty-seven breeds, and 162 wolves from North America, Europe, Asia, and Arabia. From each sample they extracted DNA from the tiny organelles within cells called mitochondria.

While the chromosome DNA of an animal cell derives from both parents, the mitochondrial DNA comes entirely from the mother. Biologists love to study mitochondrial DNA because of this simple line of descent, female-to-female-to-female. As changes called mutations occur due to copying mistakes or DNA damage, the mitochondrial DNA of two diverging lines becomes more and more different. Ancestors can be clearly identified when you are studying mitochondrial DNA, because clusters of mutations are not shuffled into new combinations like the genes on chromosomes are. They remain together as a particular sequence, a signature of that line of descent.

When Wayne looked at his canine mitochondrial DNA samples, he found that wolves and coyotes differ by about 6% in their mitochondrial DNA, while wolves and dogs differ by only 1%. Already it smelled like the wolf was the ancestor.

Wayne’s team then focused their attention on one small portion of the mitochondrial DNA called the control region, because it was known to vary a lot among mammals. Among the sixty seven breeds of dogs, Wayne’s team found a total of 26 different sequences in the control region, each differing from the others at one or a few sites. No one breed had a characteristic sequence — rather, the breeds of dogs share a common pool of genetic diversity.Wolves had 27 different sequences in the control region, none of them exactly the same as any dog sequence, but all very similar to the dog sequences, differing from them at most at 12 sites along the DNA, and usually fewer.

Coyote and jackal were a lot more different from dogs than wolves were. Every coyote and jackal sequence differed from any dog sequence by at least 20 sites, and many by far more.

That settled it. Dogs are domesticated wolves.

Using statistical methods to compare the relative similarity of the sequences, Wayne found that all the dog sequences fell into four distinct groups. The largest, containing 19 of the 26 sequences and representing 3/4 of modern dogs, resulted from a single female wolf lineage. The three smaller groups seem to represent later events when other wolves mated with the now-domesticated dogs. Domestication, it seems, didn’t happen very often, and perhaps only once.

The large number of different dog sequences, and the fact that no wolf sequences are found among them, suggests that dogs must have been separated from wolves for a long time. The oldest clear fossil evidence for dogs is 12,000 – 14,000 years ago, about when farming arose. But that’s not enough time to accumulate such a large amount of mitochondrial DNA difference. Perhaps dogs before then just didn’t look much different from wolves, and so didn’t leave dog-like fossils. Our species first developed speech and left Africa about 50,000 years ago. I bet that’s when dogs came aboard, when our hunter-gatherer ancestors first encountered them. They would have been great hunting companions.

I think Boswell would be happy to know his ancestor was a wolf. I doubt, however, I will ever be able to get my wife to overlook the biting as “wolf genetic baggage” inherited from nobel ancestors. In my house, science only stretches so far. © Txtwriter Inc

As so often happens, for reasons quite beyond me, when I am pursuing an article idea something else crops up that is highly relevant to my musings.  This was no exception.

A recent article in the Christian Science Monitor describes finding a fragment of dog bone in North America dating back some 9,400 years.  Here’s a flavour of that article.

By Associated Press / January 19, 2011

PORTLAND, MaineNearly 10,000 years ago, man’s best friend provided protection and companionship — and an occasional meal.

That’s what researchers are saying after finding a bone fragment from what they are calling the earliest confirmed domesticated dog in the Americas.

University of Maine graduate student Samuel Belknap III came across the fragment while analyzing a dried-out sample of human waste unearthed in southwest Texas in the 1970s. A carbon-dating test put the age of the bone at 9,400 years, and a DNA analysis confirmed it came from a dog — not a wolf, coyote or fox, Belknap said.

Because it was found deep inside a pile of human excrement and was the characteristic orange-brown color that bone turns when it has passed through the digestive tract, the fragment provides the earliest direct evidence that dogs — besides being used for company, security and hunting — were eaten by humans and may even have been bred as a food source, he said.

Belknap wasn’t researching dogs when he found the bone. Rather, he was looking into the diet and nutrition of the people who lived in the Lower Pecos region of Texas between 1,000 and 10,000 years ago.

The article then, a little later, goes on to say:

Dogs have played an important role in human culture for thousands of years.

There are archaeological records of dogs going back 31,000 years from a site in Belgium, 26,000 years in the Czech Republic and 15,000 years in Siberia, said Robert Wayne, a professor of evolutionary biology at UCLA and a dog evolution expert. But canine records in the New World aren’t as detailed or go back nearly as far.

Darcy Morey, a faculty member at Radford University who has studied dog evolution for decades, said a study from the 1980s dated a dog found at Danger Cave, Utah, at between 9,000 and 10,000 years old. Those dates were based not on carbon-dating or DNA tests, but on an analysis of the surrounding rock layers.

“So 9,400 years old may be the oldest, but maybe not,” Morey said in an e-mail.

Morey, whose 2010 book, “Dogs: Domestication and the Development of a Social Bond,” traces the evolution of dogs, said he is skeptical about DNA testing on a single bone fragment because dogs and wolves are so similar genetically.

My last extract is as follows:

Darcy Morey, a faculty member at Radford University who has studied dog evolution for decades, said a study from the 1980s dated a dog found at Danger Cave, Utah, at between 9,000 and 10,000 years old. Those dates were based not on carbon-dating or DNA tests, but on an analysis of the surrounding rock layers.

“So 9,400 years old may be the oldest, but maybe not,” Morey said in an e-mail.

Morey, whose 2010 book, “Dogs: Domestication and the Development of a Social Bond,” traces the evolution of dogs, said he is skeptical about DNA testing on a single bone fragment because dogs and wolves are so similar genetically.

Fascinating.

Finally, going back to the photograph at the top of the page, this came from an article here in ImpactLab.  It’s well worth a read.