I thought this had been fairly conclusively demonstrated but came across a blog recently that suggested otherwise. Anyone know what the latest research suggests?
More information here: http://www2.fiu.edu/~milesk/Genetics.htm
I’ve seen variations of the basic theme that dogs are closely related to wolfs, but not always expressed with the term ‘direct descendant’. There will be many cases where it cannot be determined if one species directly descended from another without a major intervening divergence, in this case a common ancestor or dogs and wolves that was neither. So it could be there is no way to make that determination. I look forward to hearing about more evidence about this. The last details I read about molecular evolution indicated a lack of information necessary to draw conclusions. One specific detail I recall, there was no way to determine when the divergence between coyotes and wolves occurred, which could be used as a way to derive the time frame of divergence for dogs. The length of time estimated for the divergence between dogs and wolves has a range across an order of magnitude, something like 15,000 - 150,000 years (don’t recall the specific numbers). This is a pretty substantial time difference in terms of two closely related (sub)species.
His argument seems to rest primarily on the claim that feral populations of domesticated animals typically revert to wild type within a few generations. Offhand, though, I can’t think of any examples of this: Stray cats remain smaller than wild Felix sylvestris, feral horses remain much larger than wild ponies, cattle don’t revert to aurochs, etc. Why then would it be surprising that dingoes don’t revert to wolves?
Yes, the moving hand writes, and having writ, moves on…
There’d have to be some large advantage to the wolf form over a modified dog form, and for most beasts there’s little indication that ‘optimal’ forms are at the bottom of deep stability wells.
I agree; that particular argument seemed very weak.
Very good point. I can’t think of case that fit’s that mold either. I think the only time I’ve heard that theory is from non-evolutionists. Maybe it refers to short term experiments in breeding that didn’t involve much genetic change. More likely, poor observation. Release domesticated animals into the wild, and they’re likely to intermix rapidly or be displaced by the wild population.
The one example I can think of is feral hogs. It seems to be a universal notion that over multiple generations domestic pigs gone feral will develop larger tusks, much more hair and sometimes wild boar-like bristles. They don’t completely revert, but do seem to converge to a more wild-like bauplan.
ETA: Still looking for a hard cite, rather than a secondary reference, but apparently some of these observations came out of Australia originally ( ? ).
I thought we were now treating them as the same species, as they can interbreed and produce fertile offspring.
From 2009 (Naish’s blog post was from 2006, for temporal context), there is Dogs, cats and kin: A molecular species-level phylogeny of Carnivora. From the abstract:
I’ve heard about the wild pigs, just didn’t recall it before. Do you know if this has been seen outside the presence of wild pigs?
Australian dog breeders have some of their own theories about dingos that don’t always match up to the genetic research. It was (and maybe still is) illegal to breed dingos with other dog breeds there, leading to unconfirmable stories about the results. See the story of the Australian Kelpy dog (don’t know if thats the correct spelling). I also recall some work to confirm that dingos exist naturally outside of Australia, and Australians denying that they were the same animal, maybe for nationalistic reasons, don’t recall.
Yes, but that’s not why. The convention is treat all domesticated animals as the same species as their closest wild relative. Lots of different species are able to interbreed and produce fertile offspring. The issue is whether they do so often in the wild. Since domesticated animals are, well, domestic, they don’t occur “in the wild”.
I suppose that some feral dogs have been re-absorbed into the wolf line over time. Or absorbed into the coyote line.
Here’s another paper, this one from 2007: Lessons learned from the dog genome:
And from 2010: The IGF1 small dog haplotype is derived from Middle Eastern grey wolves.:
Also from this year, we have Genome-wide SNP and haplotype analyses reveal a rich history underlying dog domestication.
And back to 2008: The legacy of domestication: accumulation of deleterious mutations in the dog genome.
And so on. I think the message here is that it is still pretty much the consensus that dogs were domesticated from gray wolves.
Stray cats may remain smaller than wild cats. *Feral *cats however do become as large as wild cats, and possibly even larger. There’s a huge difference between a stray and a feral, not least of which is that a stray’s prey will never be larger than a rat, which precludes any real advantage in large size. In contrast feral cats and wildcats will routinely prey on animals as large as hares and lambs, so the pressure for large size is significant. With similar sized prey items it is unsurprising that both feral and wild cats rapidly reach the same size.
Feral horses do not remain much larger than wild ponies. Most feral herds receive constant admixture from domestic horses, however for those few truly isolated herds the size very rapidly reverts to a large pony size regardless of ancestry.
Wild cattle don’t revert to aurochs because wild cattle only live in areas so rugged and impoverished that they are incapble of supporting cattle herding as an industry. IOW they live in areas that won’t actually support cattle growth. Coupled with this beef is valuable, so all feral populations I am aware of are subject to regular culls for marketable, ie larger, beasts. Moreover the nature of cattle husbandry means that there is a constant admixture of domsetic blood. No way you are getting an aurochs sized animal out of that
Why is it surprising that dingoes don’t revert to wolves? Firstly because all other animals do revert to wild type when left to their own devices, and secondly because all dog populations revert to a little yellow dog. If dogs were like cattle, where feral populations tended to be allsorts depending on heritage an environment, then we could say that there was simply no reversion occurring, as with cattle. However all unmanaged dog populations converge on a common body form, regardless of ancestry or environment. The puzzle is that this body form is of a little yellow dog with a narrow muzzle, pricked ears and tail curled over tha back. Always. No matter what continent or environment or ancestry uncontrolled dogs revert to a little yellow dog which is nothing like a wolf.
What that indicates very strongly is that the populations are reverting to some ancestral phenotype. But that phenotype look as much like a jackal as it does a wolf.
To show what I mean. Here is a pariah dog, a mid-eastern feral, here is a dingoan Australian feral, here is aCarolina dog, a US feral, here is an African “village dog”. You don’t need to know a lot about dogs to note how physically similar these feral dogs are, despite originating on different continents from different ancestors.
That’s the surprising part, that free-breeding dogs do all rapidly converge on a very similar body form. It’s just that the body form is nothing at all like a wolf in size, colouration or posture.
When did the wolf theory become the orthodoxy (and why)?
I can remember, as a kid (i.e., something approaching 50 years ago) reading that dogs were probably descended from jackals, or some similar animal, with maybe a little bit of wolf mixed in. More recently, I have been hearing that it is well established that it is wolves all the way down, but this guy (and, indeed Blake), who seems to know what he is talking about, makes a good case for at least a reconsideration of something like the jackal theory.
*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. *
NYT link ( Text +Multimedia , same as the link in #12).
Saw a news item about a charity that looked after farm animals when no longer used for farming and they had a couple of bulls that were definitely at, or getting on for Auroch size.
They said that most cattle were slaughtered after so many years and thats why you didn’t often see bulls of that size who were allowed to just go on living until they died of old age.
Perhaps in the heyday of the Auroch much the same situation happened due to a much smaller human presence on Earth.
Just my guess.
Clearly the blogger linked in the OP is perfectly well aware that that is the current consensus. He just thinks that there are good reasons to believe that it might not be true. (I do not think he is saying that he is sure that it is not true, just that it is not as settled as even most of the experts commonly believe.)
Frankly, unless someone here is an expert specifically on dog evolution, I doubt that anyone here can provide any better insight into the actual truth of the matter than what can be found in that blog (read with the understanding that it is, explicitly and openly, presenting a point of view that departs from the current conventional scientific wisdom).
You may note the question in the OP, which is what I was responding to:
And, as I noted, the latest research suggests that dogs are descended from gray wolves.
There’s some discussion that a few Native American dog breeds may have been domesticated from red wolves, isn’t there?
Ultimately, it doesn’t really matter - red wolves and gray wolves are both Canis lupus - they are just different subspecies. The domestic dog and dingo are likewise considered subspecies of Canis lupus. If we keep things at the binomial level, the whole lot of them are the same genus and species. Phylogenetic studies typically show a lot of crossing and backcrossing between the various subspecies. See, for example, the cladograms on page 2 of this paper (.pdf)