Feeds:
Posts
Comments

Posts Tagged ‘Iranian wolf’

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.

 

 

Read Full Post »

Canis lupus arabs— the Arabian wolf:

And Canis lupus pallipes– the Iranian wolf:

According to recent genome-wide analysis, most domestic dogs share many more genetic markers with Middle Eastern wolves than with any other subspecies.

Arabian wolves weigh 25-55 pounds. Arabian wolves have the same “small dog” gene that causes very small size in domestic dogs. They also have the fused middle toes on the front feet, a trait they share with basenjis.

Iranian wolves go 55-70 pounds, rough the same size as a typical golden retriever.

Neither of these wolves are the big “moose-killer” wolves from the northern parts of Eurasia and North America that every knows so well, that everyone sees in zoos, and that everyone thinks are the primary ancestors of the domestic dogs.  Research that in anyway compares dogs to these wolves is methodological murky, for these wolves are actually quite specialized in their behavior.  These smaller Middle Eastern wolf subspecies are much more generalist in their behavior and prey choices. It might be a better study to compare “primitive” domestic dogs, like dingoes and basenjis, with these wolves.

The unfortunate problem with this suggestion is there aren’t many of these wolves in captivity in the West, and many of those in captivity in other parts of the world are crossbred with dogs and other wolf subspecies.

But it isn’t fair to compare border collies and golden retrievers, highly specialized dog breeds, to the large northern wolves, which are highly specialized wild wolves.

But even comparisons between dogs and these wolves are problematic. These are not exactly the same wolves that were domesticated over 15,000 years ago. These wolves had the misfortune of living in the part of the world where agriculture took first took hold, and they also happen to live where people first started to herd sheep and goats. Wolves are never welcome where sheep and goats are being raised.

So these were likely the first wolves to be persecuted.

And as I’ve always noted, the effects of persecution on changing wolf behavior– both in terms of learned behavior and brain chemistry– are not considered carefully enough when trying to make comparisons between wild wolves and domestic dogs. It was likely that the original wolves were much less reactive animals than they are now and were much more willing to live near people and consider them social partners. We see this same sort of tameness in all sorts of wild dogs when they are not persecuted. Arctic foxes were not widely persecuted until recently, and they were very easy to kill and even tame as adults.

It seems to me that these ancestral Middle Eastern wolves were much more like these unpersecuted arctic foxes and not like these paranoid and emotionally reactive animals they are today.

They had to have been very easy to tame, for domestic dogs, unlike other domestic species, were not domesticated by breeding tame individuals to other tame individuals. If that were the case, we would have a clear genetic bottleneck that could be compared to wild wolf DNA to determine when dogs were domesticated. We have not found this genetic bottleneck. Instead, we have found that, as a population, domestic dogs retain much of the wolf’s genetic diversity.

That means that dogs evolved as a population of wolves. They were not domesticated by breeding tame to tame, as has been the case with virtually every other domestic species. And those domestic animals have far lower genetic diversity than their wild ancestors do.

Dogs lost genetic diversity only when they were made into breeds.

And just because domestic dogs likely derive from these two subspecies, we cannot assume that they actually became dogs, as we know them as distinct from wolves, in the Middle East.

But we just don’t know where these wolves evolved into dogs. We have some guesses.

But it is possible that wolves of this type would have followed people throughout Eurasia, and they could have started to turn into dog-like phenotypes anywhere in Eurasia– even Africa cannot be ruled out entirely.

So we know which subspecies are most closely related to dogs and could be called their most likely primary ancestors.

But everything else is still a bit of a guess.

Read Full Post »

Remember when I threw a small fit when I came across this site that claimed all the genetic evidence pointed to the coyote as the ancestor of the domestic dog?  Actually, all the genetic evidence thus far has clearly pointed to the simple reality that not only are dogs descended from the wolf (Canis lupus) and has pointed to the Middle Eastern subspecies as the main genetic stock from which all dogs are derived. This evidence also suggests that domestic dogs are a form of Canis lupus, not a unique species or derived from some other canid– be it living, dead, or imagined.

Well, here’s another dubious and poorly thought out theory about the origins of a certain breed of dog. This site claims that the basenji, which is actually very closely related to these ancestral Middle Eastern wolves, is derived from the Ethiopian wolf.

Let me show you where that is wrong:

I know that the Ethiopian wolf was once claimed to have been an African offshoot of Canis lupus. Later genomic analysis found that the Ethiopian wolf is more distantly related to the dog and wolf species than the golden jackal and the coyote. Some golden jackals, it has more recently been revealed, are actually part of the wolf and dog species. These particular wolves have not been compared to the other wolf and dog subspecies using a genome-wide analysis, but my guess is that these “African wolves” (Canis lupus lupaster) are probably closely related to the Arabian wolves and domestic dogs. These wolves do have unique mitochondrial DNA sequences, as do some Indian pallipes and Himalayan chanco wolves, but these might all prove to be much more closely related to dogs and the other Middle Eastern and South Asian wolves than the the mitochondrial DNA analysis would suggest.

However, there is no evidence that any dog is derived from the Ethiopian wolf (Canis simensis). They do hybridize with dogs and produce fertile offspring, but all of the studies on hybridization have been on the dog contribution to Ethiopian wolves. It is possible that some dogs in the Ethiopian Highlands have some contribution from Ethiopian wolf, but it is a stretch to make the claim that the basenji of  rainforests of Central Africa has anything to do with the Ethiopian wolves living in the harsh alpine country of Ethiopia.

If you want to make things very confusing, some of the newly discovered African wolves are from Ethiopia, but it is not accurate to call them Ethiopian wolves.

Canis lupus lupaster ≠ Canis simensis

And neither have been found to be ancestral to Canis lupus familiaris, which is mostly derived from Canis lupus arabs and Canis lupus pallipes.

***

This site also make a claim that black-backed jackals crossed with basenjis, too.

The only thing I need to do with that one is laugh.

Black backed jackals, let me repeat, cannot interbreed with domestic dogs.

Golden jackals, yes. Golden jackals are much more closely related to the wolf and dog species than they are to anything else that is commonly referred to as a jackal.

See where they are on the dog family phylogenetic tree pictured above? African wild dogs and dholes are actualy more closely related to wolves and dogs than black- backed jackals are.   And no hybrids between the dog and wolf species and these two canids has ever been produced, even though they should be placed in the genus Canis.  If black-backed and side-striped jackals belong in the genus Canis, then dholes and African wild dogs clearly do.

Black-backed jackals are actually the oldest extant species in the genus Canis. And no one has found that black-backed or side-striped jackals, which are found only in Sub-Saharan Africa have ever crossbred with dogs. Although many prick-eared dogs have been claimed to be part black-backed jackal, not a single hybrid has been produced so that a DNA sample could be taken.

My guess is that these hybrids simply don’t exist.

Read Full Post »

%d bloggers like this: