Hi
Is the evidence for a single domestication of the dog now stronger than a double domestication (as many websites have recently been touting)?
I look forward to your feedback.
A DNA study in 2016 found a genetic split between domesticated dogs, which the researchers claimed indicated that dogs had been domesticated twice, once in Europe and once in southeast Asia.
A second study in 2017 came to a different conclusion. That study claimed that dogs were domesticated once, but then those domesticated dogs split into a European group and an Asian group.
This is not my area of expertise, but as far as I can tell, scientists are still split in their opinions. Some believe in the double-domestication theory presented by the first study. Others believe that the second study is correct, but the scientists who believe in the single domestication theory disagree over whether that domestication occurred first in Europe or Asia.
Again, not my area of expertise, but it seems to me that scientists are still debating the issue. Both groups agree that there is a distinct genetic split between European and southeast Asian domesticated dogs. They just disagree over whether domestication occurred before or after that split.
Perhaps both models are valid! First, suppose that the transformation from wolf to dog was a very gradual process that took many thousands of years.
Multiple domestications are not uncommon. At least six species in Genus Bos (cattle etc.) were domesticated independently, along with species in its sister genus Bubalus. Multiple species of landfowl were domesticated independently, along with four species in the camel-llama family, and so on. And the early wolf-dogs were active participants in the domestication, which was beneficial to them as well. It would be surprising if multiple dog domestications did not occur.
The gray wolf had a very large range and was very mobile. As the wolf-dog gradually evolved there would be interbreeding across a vast geographic range. It’s likely there were multiple domestication epochs, but because of the continual interbreeding the genetic record is blurred or ambiguous. (The domesticated dogs form a monophyletic clade, but this does not prove that they were established in a single event. It just suggests that untamed wolf-dogs could not compete with human-dog teams.)
Am I correct in assuming that the common ancestral link between the modern wolf (from which dogs are not descended ) and the modern dog has not been determined yet? Is there any scientific name for the hypothetical common ancestral species of ancient wold from which they may have descended?
The modern grey wolf and the domesticated dog are both descended from Canis lupus, the grey wolf species which emerged a few million years ago. Dog and modern grey wolf can interbreed. (Grey wolves can also interbreed with jackals and coyotes, although they are separate species.)
Another variety of Canis lupus are the dingoes (and “singing dogs”) of Australia and New Guinea. These, I think, are descendants of domesticated wolf-dogs of Asia, which became feral again in the wilds of New Guinea and Australia. The genetic picture is complicated because many dingoes in present-day Australia are hybrids of dingoes and European dogs.
Wolves domesticated themselves, or rather, some wolves became commensal to human beings, and evolved into what are known as Pariah Dogs, a worldwide species of commensal dog still very much in evidence today (in the US you will find them on and around the Big Rez, for example), which is genetically and physically distinct from true wild wolves. It was these camp follower dogs which were subsequently “domesticated” i.e. their breeding was controlled for the purposes of developing various traits.
Clearly this process could have happened multiple times over the course of the 30,000 years dogs have been differentiated from wolves, and likewise, different strains could have become genetically separated over time.
Thank you all. Very helpful.
Just to be clear, dogs and wolves are considered to be the same species. And it should be noted that all domesticated animals are, by convention, put in the same species bucket as their closet wild ancestor. I only say “considered to be” because the whole concept of a species is a human construct, and not something that nature pays much attention to.
And, btw, all extant members of the genus Canis are interfile.
Are European and SEA dogs distinct in any other noticeable way? Like, do they have different earwax? Or any generalization you can make about SEA and E “breeds” ?
I think the problem has been mentioned above in regard to Dingos. It’s hard to find a ‘pure’ breed of domestic dog, they’ve mixed their genes so much across the globe that studying the traits of extant dogs wouldn’t give you clear results. Any noticeable difference would be found in the DNA.