Evolution

“How man’s best friend overcame laws of natural evolution”

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How man’s best friend overcame laws of natural evolution
Jan Battles

A GENETICIST says he may have solved the mystery of how 350 breeds of dog evolved from a single ancestor, the grey wolf.
Matthew Webster of the Smurfit Institute of Genetics at Trinity College, Dublin, and colleagues at Uppsala University, Sweden, say the domestication of dogs may be allowing them to override the natural laws governing evolution.

They suggest natural selection, which ensures the survival of the fittest and weeds out genetic mutations that don’t provide a survival advantage, was relaxed when dogs became domesticated. Living with people allowed harmful genetic variations to flourish that would never have survived in the wild.

This interference with nature could also explain why domestic dogs developed an array of diseases such as cancer, heart disease and epilepsy.

“Dogs exhibit more variation in size, appearance and behaviour than any other mammal, but the source of this huge diversity is something of a mystery,” said Webster. “Dogs were domesticated from wolves very recently, on an evolutionary timescale, so all the variability seen in different dog breeds today has been generated in a relatively short time.”

Scientists are still puzzled as to how such a scale of development could have taken place in a relatively short evolutionary timescale of 15,000 years.

Dogs evolved when wolves and early humans, which had been rivals for food, developed a mutually beneficial relationship. People began selecting those with desirable traits, such as guarding against intruders or hunting for food. In turn they were fed and given shelter.

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9 Replies to ““How man’s best friend overcame laws of natural evolution”

  1. 1
    zapatero says:

    On a related topic, a program in Russia has successfully tamed Siberian foxes over the last 45 years:

    “They stare you in the face, wag their tails and whine with joy when anyone approaches. No, these are not dogs but a domesticated breed of fox that looks and behaves just like man’s best friend. After 45 years of selective breeding, and almost as many fox generations, scientists have produced what nature could not — a completely tame fox which eagerly follows his master’s gaze. Foxes bred on a farm in Russian Siberia since 1959 not only look like dogs, they act like them too in their ability to read someone’s face for visual cues on what they are expected to do.”

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  2. 2
    Tim Sverduk says:

    Hmmm… only 15,000 years to get 350 different dog breeds from a small population of domesticated wolves? I wonder how long it would take to go from a small human population (say 8 adults) to get the 20 or 30 different human groups – i.e., Pacific-Islanders, European, African, Asian, Native American … etc, etc? Maybe 5,000 or 6,000 years? Also, just by eye-balling the human variations, it looks like the human groups are much more similar to each other than the dog groups are similar to each other.

  3. 3
    tribune7 says:

    So are wolves and dogs still considered separate species?

  4. 4

    It’s more of a guideline, really.

  5. 5
    SatyaMevaJayate says:

    The speciation definition I think is most apt is the strong one rather than the weak one that the darwinian crowd prefers…

    So if wolves can still breed with dogs, they all belong to a single species…

    See Richar Miltons’ arguments for an elaborate debunking of the speciation arguments put forward by the darwining mob
    http://www.alternativescience......ations.htm

    So if we go by the weak definition of “reproductively isolated”, then numerous cult groups whose members only marry within should be termed as seperate species.

  6. 6
    BarryA says:

    “So are wolves and dogs still considered separate species?”

    That depends on how one defines “species.” The most common definition is “groups of individuals that can interbreed, at least potentially, with one another and not other groups.” Futuyma, “Evolution,” 11.

    Under this definition dogs and wolves are separate strains of the same species, because dog-wolf hybrids are fairly common.

  7. 7
    BC says:

    > I wonder how long it would take to go from a small human population (say 8 adults) to get the 20 or 30 different human groups – i.e., Pacific-Islanders, European, African, Asian, Native American … etc, etc? Maybe 5,000 or 6,000 years?

    Creationists believe that Noah’s flood happened around 2350 BC – around 4350 years ago. Of course, there’s numerous problems with such an idea – for example, when King Tut was ruling over Egypt, overseeing millions of people, a mere 1,000 years after the flood requires that the technologically primitive society has very high reproductive rates between 2350 BC and 1250 BC, followed by rather low reproductive rates for the next 3000 years. Another big problem involves the fact that Egyptian dynasties stretch back to 3000 BC – and continue right through the date of 2350 BC.

    > only 15,000 years to get 350 different dog breeds from a small population of domesticated wolves? … Also, just by eye-balling the human variations, it looks like the human groups are much more similar to each other than the dog groups are similar to each other.

    Different species have different amounts of variations between individuals. Humans have very low variation. Chimpanzees, on the other hand, have significantly more variation (despite their fewer numbers). Separating a species (for example, dogs) into 350 different breeds is something that depends very heavily on the existing genetic variation within the wolf population. Further, artificial selection (where someone is choosing traits) is going to cause very heavy selection pressure on the physical appearance and behavioral tendencies of a species, because that’s what the breeder is selecting for. Natural selection is going to chose more hidden traits – like blood-types and resistence to disease.

    All in all, I don’t really see how this article says anything bad about naturalistic evolution. If anything, it shows that artificial selection over a few hundred years is a very powerful force. If naturalistic evolution approaches anything close to that selection rate, then naturalistic evolution over millions of years is a pretty powerful force. It’s also notable that Darwin talked about the power of artifical selection as a model for understanding naturalistic evolution: “what is equally or more important, we shall see how great is the power of man in accumulating by his Selection successive slight variations… [in nature] there is a frequently recurring struggle for existence, it follows that any being, if it vary however slightly in any manner profitable to itself, under the complex and sometimes varying conditions of life, will have a better chance of surviving, and thus be naturally selected.”

  8. 8
    BarryA says:

    My schnauzer Wally and I were out for a walk this morning. I know it’s hard to think of anything named “Wally” as anything other than kind and gentle, but he kept yanking at his leash trying to get loose and chase rabbits. I said, “Wally, I know you’re a fierce descendant of wolves, but you’ve got to calm down.”

    Then there was the time my wife appealed to canine evolutionary psychology when Wally jumped up in the bed. “Oh leave him alone,” she said. “He just wants to be part of the pack.”

  9. 9
    jhudson says:

    This seems to be another case where the power of mutation and natural selection are modified to be whatever they need to be to explain whatever events occurred in the past. In the case of non-domestic animals it is the pressure of natural selection acting on populations of organisms which is said to creat the diversity we see in life; in domestic animals it is the relaxation of that pressure that creates the diversity we see in dogs.

    Of course, they overlook intelligence as a factor, even though it is undeniably a factor in the case of domestic dogs.

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