On The Origin of Dog…

33_dog_sittingDogs are dogs. While there is virtually no doubt that dogs originated from wolves, they are not wolves, and according to some scientific evidence may have ceased to be wolves as long ago as 100,000+ years. Although that is a short blip geologically, it is, nonetheless, a pretty long time to not be something.

Various studies in the last 20 years have looked at the origins of dogs via their mitochondrial DNA. The results of these studies have raised some interesting theories on the origin of this species. While DNA that determines eye color, curly hair, and earlobe shape, comes half from mom and half from dad, mitochondrial DNA, on the other hand,

comes entirely from the mitochondrial DNA of the mother. In normal sexual reproduction genetic change from one generation to the next is very rapid, as the parental genes are mixed and remixed in new combinations. Mitochondrial DNA, in contrast, can change only by mutation, which takes place quite slowly — at a rate of around one or two percent every 100,000 years. (The Truth About Dogs, Part Two, by Stephen Budiansky, The Atlantic Online, July 1999).

Because it changes so very slowly, it can be used to gauge when dogs and wolves first separated, and the results seem to conclude that it happened about 135,000 years ago! There are indications that dogs split from various wolf populations around the world and that there was some interbreeding between wolves and dogs. But, the split did not occur very often, nor was there a lot of interbreeding. Dogs, it seems, left their wild brethren behind and integrated pretty quickly into human society. It also appears that humans and dogs may have conjoined before humans were fully human.

Archeological evidence tells a different, but not necessarily incompatible story. The earliest canine fossil records seem to 81_dog_dreams of bones-01IMG_1304Russian plain about 15-17,000 years ago (though others state that it is southern China, which is also the only fossil record that indicates dogs were used as a food source). Recent studies (2011) by paleontologists in the Czech Republic found dogs from the paleolithic period, one of which was buried with a large bone in its mouth that was “clearly placed in the dog’s mouth after death indicat[ing] that a human being was involved in the burial, as no other known animal would be capable of doing such a thing.” (http://phys.org/news/2011-10-evidence-domestication-dogs-paleolithic-period.html). According to Wikipedia, there was a dog found buried with a human in Israel which dates from 12,000 years ago, and a burial site in Germany called Bonn-Oberkassel with joint human and dog interments dating to 14,000 years ago.

Interestingly, there is no western European cave art depicting dogs, perhaps suggesting, that before 16,000 BC dogs were unknown 12_dog_run horusin western Europe. However, not all animals known to early hominids were depicted in cave art, nor do we know the reason cave art was created. So, does the lack of canine portraiture indicate that dogs were unknown to early man, or just not depicted in art for some reason? Dogs did however, make the art scene in Ancient Egypt, appearing on the walls of burial sites dating back to at least 3500 BC.

I have barely scratched the surface of the current debate about the time and place that dogs became dogs and commenced on this journey with their human companions. I think, however, the important thing to remember is that whether you look at DNA or at the fossil record, dogs and man were clearly besties by 10-15,000 years ago, making them the first domesticated animal, and truly deserving of the title: Man’s Best Friend.

Next Week: Why it matters that dogs are not wolves.

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2 Comments
  1. Mike Morales says:

    Julie,

    I’ve followed this pretty casually, but my understanding is that the mitochondrial DNA evidence is not really holding up. The reference you quoted was from 1999. Then, the main advantage of mitochondrial DNA sequencing is that it was possible. Advances in sequencing technology have made whole genome sequencing fairly easy, and I think the evidence is now pointing toward a date that corresponds much more closely to the archeological dates (20-30k years ago). If I get a chance, I’ll send you a couple of references.

    • Julie Smith says:

      Hi Mike,

      Thanks for taking the time to read and respond to my blog. Any pertinent information you may have would be welcome. I am always interested in learning more, and clarification is always good! You are correct that the Atlantic article was from 1999, but I did find other sources from 2002 through 2005 which looked at dog origins and that suggested a variety of different timelines for dog origins. Thus, I decided to offer the theory that dogs perhaps left their wolf cousins 100,000+ years ago, and that archeological evidence seems to support a later split. The critical point of the whole blog was that dogs are not wolves and have not been wolves for a long time, and that they were the first domesticated animal. Stay tuned for next week’s blog on why that matters! Julie
      PS: LOVE your email address…how did I know that was you before I looked at your name? 🙂 love to Marian, Paul, and Ringo.

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