While reading David Quammen’s illustrated edition of Charles Darwin’s On the Origin of Species a few months ago, I learned that not only was Darwin an avid breeder of fancy pigeons, but also that Darwin thought that the sheer variety of domesticated dog breeds meant that dogs couldn’t have evolved from a common ancestor.
This surprised me.
The idea that dogs descended from a common ancestor — specifically some sort of prehistoric wolf — is so deeply encoded in my background scientific assumptions that I just assumed that Darwin must have started it.
Learning that he didn’t has me questioning all sorts of things. Starting with the most basic — my own ability to read.
Maybe I just misread that bit
After all, Darwin used the the immense variations that humans bred into their fancy pigeons as the basis for his theory of artificial selection (the precursor for his theory of natural selection). Faced with all that diversity, Darwin was still able to point to a single pigeon species — the rock pigeon — and say (essentially), “That’s the one. Fancy pigeons all evolved from that bird there.”
From this, it seems logical to assume that Darwin would also have been unfazed by the diversity in domesticated dog breeds. Surely he would have also been able to say, “yes, truly, it is simply amazing what we breeders can achieve when we put our minds to it,” and see that the logical arguments he used to deduce to a common pigeon ancestor could also apply to dogs.
Nope. Let’s go to the source:
“I do not believe, as we shall presently see, that all our dogs have descended from any one wild species; but, in the case of some other domestic races, there is presumptive, or even strong evidence in favour of this view.”Darwin, On the Origin of the Species, p. 24
I really don’t see how Darwin could have been much clearer. He was not the person who first proposed that dogs were descended from wolves. As far as Darwin could tell, dogs didn’t have a common ancestor at all.
So now I’m wondering if scientists still think dogs are descended from wolves at all.
Are dogs descended from wolves?
Yes, but perhaps not the wolf we originally thought.
For years, dogs have been described as being descended from the grey wolf. But according to a 2015 LiveScience article, Ancient Wolf DNA Could Solve Dog Origin Mystery, a recent DNA study suggests that instead of being descended from the grey wolf, dogs may simply share a common ancestor with it — specifically a certain prehistoric wolf that lived in Siberia’s Taimyr Peninsula more than 27,000 years ago.
“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.
“Scientists once thought that dogs descended from gray wolves. Now, through genetic studies, researchers know that dogs and wolves share a common ancestor instead of a direct lineage.”Becky Oskin, “Ancient Wolf DNA Could Solve Dog Origin Mystery”, LiveScience, 21 May 2015
The really cool thing is that according to this LiveScience article, certain breeds of dogs, including Siberian huskies, Chinese Shar-Peis, Greenland dogs, and the Finnish spitz still carry genes that can be traced directly back to this ancient Taimyr wolf.
Did you notice the part where I said only some dog breeds carry genes that can be traced back to this ancient wolf?
Yeah, it turns out the question of how dogs are descended from wolves is much more complicated than I expected.
As far as I can tell, scientists still believe that dogs are descended from an extinct wolf species that lived between 15,000 and 40,000 years ago. But there’s a lot of disagreement over where and when dogs were domesticated.
A 2013 article in the journal Nature argues that European hunter-gatherers first domesticated dogs some 20,000 years ago. Two years later, another study was published in Nature that said, no, domestic dogs probably actually originated in the southern portion of East Asia some 33,000 years ago. Yet another study, published in 2015 in the Proceedings of the Natural Academy of Sciences of the United States of America (PNAS) points to a third possible location — Central Asia. A 2016 study published in Science suggests that dogs were domesticated from two separate wolf populations in two different parts of the Old World.
Clearly, scientists haven’t quite figured out where and when dogs first appeared in the fossil record, or how dogs became domesticated in the first place. Given all this, I find myself having more sympathy with Darwin’s argument that no one common ancestor could possibly account for all the variations in modern dog breeds. And that’s before my husband pointed out that there’s extensive debate about the role epigenetics (chemical modifications made to DNA that don’t change the basic base-pair sequence) may have played in the development of modern dogs as well.
The question of how dogs became domesticated seems like a story worth digging into. But it’s also a pretty complicated one, so I’d better save it for another day.
- “Why was Darwin so obsessed with pigeons?” (Caterpickles)
- Ancient Wolf DNA Could Solve Dog Origin Mystery (LiveScience)
- How Accurate is Alpha’s Theory of Dog Domestication (Smithsonian Magazine)
- How Epigenetics Is Improving our Understanding of Domestication in Animals (What Is Epigenetics)
- Out of southern East Asia: The natural history of domestic dogs across the world (Nature)
- Genetic structure of village dogs reveals a Central Asian domestication origin (PNAS)
- Prehistoric genome reveal European origin of dogs (Nature)
- Genome and archeological evidence suggest dual origin of domestic dogs (Science)