Let’s say you’ve been asked to identify a tree.
And all you’ve been given are two twigs.
You might get it right.
If you’re educated, you might get within the right genus, but getting the exact species is probably next to impossible.
Now, let’s say someone gave you a log and asked you to do the same thing.
Logs are a bigger part of the tree. They have bark, and you can examine the hardness and texture of the wood.
You are much more likely to get it right.
Currently, there is a debate between geneticists about the origin of the domestic dog. One school, which uses studies mtDNA and y-chromosomes, say that dogs have origins in either southern China or Southeast Asia. The other, which has examined nearly 50,000 SNP’s (single-nucleotide polymorphisms) within the dog genome and found that dogs are most similar in their genome to Middle Eastern wolves.
The ones who are looking at mtDNA and y-chromosomes are looking at twigs. They are but a tiny fraction of the genome compared to the 50,000 SNP’s. All mtDNA does is trace maternal heritage, and it’s possible to get severe errors with it, such as under-estimating when savanna and forest elephants split or diving the Indian wolf a separate species. The exact same errors can be made with y-chromosome analysis. The only difference is that y-chromosome analysis looks at paternal heritage.
That’s why I’m generally dismissive of the new studies (this one and this one) that say dogs are derived from Southeast Asia or East Asian wolves. There are no Southeast Asian wolves, except for a few that live in Myanmar (Burma), so it’s always been a very silly thing for people to puff up about. Except for those Burmese wolves, there have never been Canis lupus wolves in Southeast Asia, but there have been golden jackals and their relativels. Similarly, Southern China is on on the periphery of the wolf’s range– and always has been.
The landmark study of dog and wolf nuclear DNA was performed at UCLA. Peter Savolaninen, who is the major proponent of the theory that dog originated in East Asia, complains that this study didn’t include any wolves from south of the Yangtze. It didn’t need to. It included dingoess, which have origins in Southeast Asian domestic dogs. They take the place of that much harder to procure sample.
The problem with these “twig” studies is they are much easier to perform and analyze than the genome-wide analyses.
I’m much more willing to trust a study that used a “log” than one that looked at “twigs.”
***
Mark Derr performs a devastating take-down of the theory that dogs originated in East Asia in How the Dog Became the Dog. He points out that the time period for which dogs supposedly originated in East Asia does not correspond with any archaeological data. Dogs don’t appear in that part of the world until thousands of years after they appear in other parts of the world.
Now, just because dogs appear to be most closely related to Middle Eastern wolves does not mean that they became morphologically distinct from wolves there. Derr wrote that the first morphologically distinct dogs would be found in Central Asia– and just a few months later, a 33,000-year-old skull of wolf with domestication features was discovered in the Altai Republic.
It’s also an error to look for an origin time and place for domestic dogs. It actually involved relations between people and wolves that took place over tens of thousands of years. Middle Eastern wolves were the basis for most dogs we have today, but some of those from East Asia– including the dingo– do show some influence from Chinese wolves. Some European breeds show some influence from European wolves.
Speaking from my limited experience, autosomal snps are gonna tell you a lot more than either MtDNA or Y-DNA. Used together though, they can tell a really interesting story.
I think in many cases, selection for “type” or even breed has muddied the waters. You can eliminate a “Y” or an “MTDNA” very quickly in a breeding program. Someone once made a comment that I had one of the few Belgian Sheepdogs decended from a particular bitch in the maternal line. And in fact, my dogs no longer have her MTDNA because I kept a male to continue my line — yet obviously, this bitch is an ancestor. How would one detect if her “K” black gene is the one inherited or if it came from this dog’s sire? You would need much better, intensive investigation to verify it. Also, a lot of breeds get omitted (I’ve yet to see a study showing relationships between Bouviers, Belgians, Dutch shepherds, Briards, Beaucerons and Picardy shepherds although historical information indicates very close relationships). And unfortunately, a lot of these studies are trying to “prove” the pet theory of the researcher. Add to this that it’s entirely possible that extinction of various wolf sub species and changing ranges I expect that there will be claims and counter claims for some decades to come.
My personal view is that we probably domesticated wolves as soon as we encountered them, and that it occured multiple times — including some crosses that occured pretty recently.
Peggy Richter.
I watched a lecture by Robert Wayne of UCLA online a couple of months ago, and he said a real problem is that modern Western dog breeds have lost much of their mtDNA diversity through breed formation.
[…] It’s like looking a truckload of twigs, when you should be looking at a truckload of logs. […]
Our ancestors left Africa 120 000 – 60 000 years ago. When they crossed the Red Sea, they arrived in Middle East. Then some groups departed to go to the North, while others headed to East.
Anyway, before that, I strongly believe, is the time and place they met their first dogs / wolves.
The reason, I think, why the Far-East is so stressed in this question about the dog’s origins, is that those dogs preserved their old genetic type due to the isolation in the wide & far area – and that the later culture strongly sheltered its members, so also dogs, from any outer infuences during the latest thousand year. And these both facts show in the genes of a Chow or a Pekingese – they seem to closer to the wolf than any Retriever or a Shepard Dog.
[…] Twigs versus logs and the origin of the origin of the domestic dog (Critiques the supposed proof from y chromosome and mtDNA analysis that claims dogs have an East Asian origin. The bulk of the evidence points to the Middle East as the main source for domestic dog genetic diversity.) Share this:TwitterFacebookRedditPrintDiggStumbleUponLinkedInEmailLike this:LikeBe the first to like this post. […]
[…] that dogs were derived from East Asian wolves and that there was only a single domestication event. Most of this studies that point to East Asia as the place of origin have used either mitochondrial D…. However, a study that examined the largest part of the genome of dogs and wolves found that most […]
[…] that dogs were derived from East Asian wolves and that there was only a single domestication event. Most of this studies that point to East Asia as the place of origin have used either mitochondrial D…. However, a study that examined the largest part of the genome of dogs and wolves found that most […]
[…] that dogs were derived from East Asian wolves and that there was only a single domestication event. Most of this studies that point to East Asia as the place of origin have used either mitochondrial D…. However, a study that examined the largest part of the genome of dogs and wolves found that most […]
[…] Twigs versus logs and the origin of the domestic dog […]
[…] Twigs versus logs and the origin of the domestic dog by Scottie Westfall III […]