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Freethinker
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National Geographic article:

==================================

Humans and dogs have been sledding together for nearly 10,000 years

Sled dogs have also evolved adaptations to their harsh lifestyle, such as the ability to thrive on high-fat diets, a new study says.
By Jason Bittel

PUBLISHED June 25, 2020

Greenland sled dogs, a fluffy, curly-tailed canine native to the harsh Arctic tundra, could be the oldest dog breed, according to the first study to take a deep dive into the animals’ genetic history. The sled dog branch of the family tree, which includes various types of huskies and malamutes, broke off from the rest of the dogs around 9,500 years ago, versus something like a labradoodle, which only became a breed in 1989.

Scientists know that dogs likely evolved from Eurasian wolves, but exactly when or where that transformation took place is a matter of great mystery. To better understand the genetics of sled dogs and their place in the world, scientists sequenced the genome of a dog from Siberia’s Zhokhov archaeological site, dating to around 9,500 years ago.

“I was actually anticipating that we would find some sort of precursor of domestic dogs,” says lead author Mikkel-Holger Sinding, a paleogeneticist and Ph.D. student at the University of Copenhagen in Denmark.

Instead, he and his colleagues found today’s sled dogs and the Zhokhov dog descended from the same branch. “It means that all dogs must have diversified earlier than this,” he says.

That’s a huge finding, Sinding says, because it provides the “first firm date for diversification in dogs”—in itself an important clue in the mystery of dog domestication.

The analysis, which compared genes between ancient and modern dog sled dogs with those of other breeds, also revealed all sorts of fascinating and unique adaptations to Arctic life, such as the ability to thrive on a high-fat diet.

“One of the biggest differences between a brown bear and a polar bear is that the polar bear has a specific genetic adaptation for eating lots of blubber. And we see almost precisely the same solution in [sled] dogs,” Sinding says.

This makes logical sense, as the Inuit and Thule peoples of the Arctic and their working dogs have survived for thousands of years by hunting blubber-rich marine mammals, like seals and whales.

The scientists also compared the Zhokhov dog’s DNA with an even more ancient canid—a Siberian Pleistocene wolf that lived about 33,000 years ago. Together with genomes from modern wolves and domesticated dogs, the team revealed that, remarkably, sled dogs haven’t interbred with gray wolves in the past 9,500 years, unlike other breeds. This is especially strange, given that indigenous peoples have documented dog-wolf pairings. The fact that traces of wolf genetics don’t show up in the Greenland sled dogs’ genome suggests that either hybrids didn’t survive well, or that there was some reason humans did not breed them.

The research also showed that sled dog genomes contain mutations related to their cold environments, such as running and pulling sleds in low-oxygen conditions.

“So, being able to still exercise even if you can’t catch a breath,” says Elaine Ostrander, a geneticist at the National Institutes of Health who studies canine genomes but was not part of the study.

Another mutation allows sled dogs to highly regulate body temperatures, says Ostrander—necessary not only to survive the cold, but to cool down after a period of exertion.

This bears a striking resemblance to a genetic mutation in the woolly mammoth, another cold-adapted creature that’s able to fine-tune its temperature, says Sinding.

Owning a happy sled dog

Curiously, such traits are still present in today’s pooches, which provides useful guidance for pet owners—particularly those with purebreds.

“In addition to all the geographic and evolutionary connections they make [in the study],” Ostrander says, “the connection to how we should be thinking about our modern pets is really important.”

For instance, based on the animals’ genes, Sinding advises sled dog owners to avoid starchy, high-carb diets. “Give them protein and fat,” he says. “That’s what they developed for.”

Likewise, the study shows these dogs evolved to move, not “sit around in an apartment all day,” Ostrander says, suggesting lots of exercise and task-based play is crucial.

Pet owners might also want to consider climate before choosing a new pup, she says. Sled dogs get overheated easily and are more lethargic in hot or humid environments, but when you "take them into the snow, you see how happy they are," she says. (Read about what makes a good sled dog.)

Next up, Sinding wants to unravel the mystery of what happened in canid evolution between the sled dogs of Zhokhov and the dogs of present day.

“There’s a 9,500-year gap,” he says. “There’s so much history between these two points that we want to investigate.”

LINK




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Posts: 42081 | Location: 10,150 Feet Above Sea Level in Colorado | Registered: April 04, 2002Reply With QuoteReport This Post
hello darkness
my old friend
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Interesting article. I'm still trying to figure out how we got from wolves to Chihuahua's?
 
Posts: 6683 | Location: West Jordan, Utah | Registered: June 19, 2007Reply With QuoteReport This Post
Freethinker
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Originally posted by gw3971:
I'm still trying to figure out how we got from wolves to Chihuahua's?


Breeding and selection for specific traits by humans, i.e., directed evolution.

Here is an article about the deliberate attempt to domesticate the silver fox in Russia through deliberate selection of desired traits, and which succeeded to a significant degree in a remarkably short time.




“The fundamental cause of trouble in the world today is that the stupid are cocksure while the intelligent are full of doubt.”
— Bertrand Russell
 
Posts: 42081 | Location: 10,150 Feet Above Sea Level in Colorado | Registered: April 04, 2002Reply With QuoteReport This Post
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That was a fascinating read, and a good look at the politicizing of science in another era.

I still wonder about the timeline from wolves to chihuahuas though. The study cited above went from wild foxes to tame foxes in 6 to 15 generations. Although some relatively minor (to me) physical differences were observed, they aren't the magnitude of wolf to chihuahua.




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Posts: 2682 | Location: Carlsbad NM/ Augusta GA | Registered: July 15, 2007Reply With QuoteReport This Post
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quote:
Originally posted by IntrepidTraveler:
That was a fascinating read, and a good look at the politicizing of science in another era.

I still wonder about the timeline from wolves to chihuahuas though. The study cited above went from wild foxes to tame foxes in 6 to 15 generations. Although some relatively minor (to me) physical differences were observed, they aren't the magnitude of wolf to chihuahua.


One gene between tiny dogs and giant ones?
 
Posts: 2446 | Location: KY | Registered: October 20, 2001Reply With QuoteReport This Post
Freethinker
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Originally posted by IntrepidTraveler:
[T]hey aren't the magnitude of wolf to chihuahua.


The Russian experiment was/is conducted under very unusual conditions. It would be interesting to know how breeders were able to affect things like massive size change and other characteristics without having the numbers of animals and the controls of the silver fox project.

And although it’s highly unlikely we will ever learn, it would be interesting to know how the first wolf was domesticated enough to serve as the basis for turning them into dogs. But even that’s probably not what happened; it would have been necessary for not just one animal to be tamed enough to hang around with humans, but at least a breeding pair. I suspect that like so many things, it probably progressed by fits and starts in the beginning.

As somewhat of an aside, for anyone more interested in domestication of animals and their characteristics such as floppy ears on dogs, I can recommend the book The Goodness Paradox by Richard Wrangham. The book covers much more than that, but I found that section to be particularly interesting.

https://smile.amazon.com/s?k=t...&ref=nb_sb_ss_i_1_11




“The fundamental cause of trouble in the world today is that the stupid are cocksure while the intelligent are full of doubt.”
— Bertrand Russell
 
Posts: 42081 | Location: 10,150 Feet Above Sea Level in Colorado | Registered: April 04, 2002Reply With QuoteReport This Post
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Not being an expert on anything, I’m assuming the chihuahua is a bred descendant of some hot-weather wolf/canine that evolved to become smaller due to heat, and then over time the smallest of those were chosen and bred by humans.

Animals in hot environments tend (not always) to be smaller than the same species/similar species in more temperate or colder climates.
 
Posts: 1914 | Location: S. FL | Registered: October 26, 2010Reply With QuoteReport This Post
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You only have to look at the English Bulldog to see what can happen in a short time frame.

The current dog looks more like the fire plug that the old dog used to pee on.



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Posts: 5701 | Location: Somewhere looking for ammo that nobody has at a place I haven't been to for a pistol I couldn't live without... | Registered: December 02, 2014Reply With QuoteReport This Post
Live Slow,
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"I won't be wronged, I won't be insulted, and I won't be laid a hand on. I don't do these things to other people and I require the same from them."
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Posts: 3147 | Location: California | Registered: May 31, 2004Reply With QuoteReport This Post
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People forget that on an evolutionary scale, animals like dogs can be bred beginning around 1 year old - so compared to humans who likely started breeding around 14 years old (thousands of years ago) but now that is (on average) significantly later (22 years in 1980 and now 27 years in 2020 for America), you are looking at a huge difference.

You could have 15-20 generations of dogs bred in the time it takes a single human to come of age. So dogs can be selectively bred / modified for traits (size, demeanor, etc) far faster than humans are genetically changed.
 
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Jack of All Trades,
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Then there's my own theory, the more breeding and further away they get from their wolf roots, the more problems breeds have.




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