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Tuesday, October 7, 2008

Proto-Dog and Human Subspecies

I just saw a fascinating documentary on Nova that dealt with the evolution of the domestic dog. To summarize, there’s now a theory with some convincing genetic evidence that wolves were not domesticated and bred by man to become dogs over thousands of years, but that they self-evolved almost instantly. That flies in the face of generally accepted theories on evolution, and raises some very interesting questions and premises for Science Fiction.

The documentary offered evidence that all modern dogs are descended from a new species that evolved about 15,000 years ago in Eastern Asia, called Proto-Dog. The new species for all practical purposes “popped” into existence when humans began living in large enough groups to create garbage dumps. Wolves would gather to forage in these garbage dumps and among those wolves were most likely a few that were less afraid of humans and allowed themselves to be approached and captured, or their pups taken and raised. These domesticated wolves became dogs, but it didn’t happen over thousands of years as many believed, it may have happened in just a few generations—perhaps in one human lifetime? How? How did a new species of canine evolve in the mere blink of an eye on the evolutionary scale? The research holds some surprises.


Studies led to research on a group of silver foxes raised for their pelts in Russia in the 1950s. In order to raise foxes that were easier to manage, Russian scientist Dmitri Belyaev conducted experiments where a gloved handler reached into the cages to test the animal’s response. Those foxes that cowered or bit were not selected for breeding. Those that were accepting of the humans were bred. The results? Within a few generations not only was a more docile breed of fox created, but the foxes began exhibiting dog-like appearance, and even their coat colors changed to black and white coat patterns—like some breeds of dogs--instead of the solid dark or smokey coat of this particular breed of fox. They also began behaving very much like a domestic dog and socializing with humans. The hypothesis is that there are genetics links between so-called docile genes and other traits in the DNA and these were expressed when the selected foxes were bred, resulting in almost instantaneous evolution into the dog-foxes, or quite possibly, a new subspecies.

Going back to the spontaneous evolution of wolves, they theorize that once certain wolves were captured and domesticated, then crossed with other “docile gene” mates and producing pup-cubs, the other linked genes began to express themselves in physical change. These docile genes worked like genetic preprogramming. Once conditions were right for domestication, the wolves very rapidly evolved or adapted into a new species better suited to co-exist and co-rely on humans. They also no longer needed to hunt in packs to survive, so physical changes to teeth, jaws, and brains also began occurring at a slower rate along with the docile gene influences. In only a few generations, a breed that was probably very different from wolves existed. Voila. Spontaneous evolution.

In P2PC, my world building involves many different subspecies of humans who evolved with physical differences because of the environments of the planets they settled. I had concerns with this idea because this takes place only 1500 years in our future, and according to accepted theories of evolution, physical changes would require tens of thousands if not hundreds of thousands of years. Now it appears very likely that this would be entirely possible as unknown genetic links come into play in specific gene pools that could cause much faster, more drastic changes. A thousand years to evolve into several subspecies now seems very much within the realm of “suspension of disbelief.”

Want to read more? Check out this link.
How Stuff Works: How Dogs Work--The Evolution of Dogs

4 comments:

  1. This is interesting since you're dealing with more than one species here. Wolves fall into the canine catagory and a fox is more of a descendent of the feline. Note the eliptical shape of the pupils. So, this theory is not restricted to more than one species. This gives more weight to the effects it could have on homo sapian and the fact we could have and could evolve and adapt genetically faster than first believed.

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  2. The Canids, which includes dogs, wolves and foxes seem to have genetic make-up that makes them especially easy to breed for new traits. I read a paper on this once, it had to do with were and how their genes line up on individual chromosomes and with the large number of genes they have that turn off and on other genes in fetal development.

    This is why there are so many more and different types of dogs than say cats, or horses. Equine and feline genes just don't have the tool kit to have so many options.

    Cats just don't have the genes to develop a feline version of a Chihuahua or a St.Bernard.
    For example an Irish Setter or Collie is very different in both looks and behavior than a wolf of about the same size. Their bones and muscles are different not just their brains. But with an 9 pound cat and a small wild cat of the same size there is very little body difference, even with extreme exotics like smashed faced Persians and snaky Siamese. The main difference is that domestic cats have 1/3 fewer neurons in their brains, and produce about 1/fewer stress (fight/flight) hormones than wild cats. There is even a theory that cat's were not really domesticated the way dogs, cow or sheep were, but domesticated themselves. The evidence for this has to do with domestic genes in extant wild populations and stuff like that and I can't remember all the details.


    There is another theory that having a genetic make-up that was easily changed is why some animals were domesticated, and others were not. That's why we have domestic dogs, pigs and sheep, but not domestic deer, large cats, bears or antelope.

    Sorry, for the rant, see what working for over 20 years as an educator in a Zoo does to you :-)

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  3. Hi Dawn. *waves* Bet you can see why this interested me. :)

    Hi mfitz. That's an interesting point about horses and cats. There does seem to be a lot less diversity in most other domesticated species.

    Thanks for your comments. Thought provoking stuff.

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  4. Oh so interesting. Who says cats are domesticated? LOL
    They think the own the place and the human. If anything my cat thinks he's domesticated me.

    Then you have apes...

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