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Tuesday, 12 March 2013

From Wolf to Woof

From Wolf to Woof

All breeds of domestic dog, Canis lupus familiaris, are the same species but exhibit extreme variation. Furthermore, modern genetic analytical techniques have shown that, regardless of the breed, the domestic dog’s ancestor is the gray wolf, Canis lupus. Gray wolves still exist to this day.
DISCUSS the variation in domestic dog populations and in wild gray wolf populations.
In your answer you should:
  • identify some differences between the gray wolf and domestic dog breeds,
  • explain how these differences may have come about, and
  • explain why gray wolves look so similar, while different breeds of domestic dogs look so different.

Emily's Response

The domestic dog is a very interesting species of animal. There is a huge variety of breeds, ranging from the tiny Chihuahua, standing at about 6 inches tall, to the huge Irish Wolfhound, which is taller than the average human while standing on its back legs. But these dogs all have one thing in common; they are all related to Canis lupus, the grey wolf. There has been some debate over whether this is true or not, but modern genetic analytical techniques has helped prove that the domestic dog's DNA is over 99% identical to that of the grey wolf. Even though this has been proven, it does not change the fact that there is so much variation in the domestic dog species, yet there is little variation in the grey wolf species. Why is this? Read on and find out.
Even though the domestic dog and the grey wolf have nearly identical DNA, there are many differences between them: physical, mental and behavioural. These may have come about by mutations from the breeding of brother and sister wolf-dogs. Close inbreeding causes mutations, and many of these would be "bad" mutations, such as heart problems, blindness etc. This would happen because the wolf-dog siblings would share the same DNA, which may cause the insertion, deletion or substitution of the correct genes. But some of the mutations may be desirable, such as a curly tail, and you would continue to breed this wolf-dog to pass this desirable mutation on. Grey wolves look quite similar, while domestic dogs have a huge degree of variation. The wolves look so similar because there is no artificial selection in the wild; there is natural selection, which chooses the fastest, strongest and most intelligent wolves to carry on their genes. Because of this natural selection, there is little inbreeding, so mutations are uncommon. The domestic dog, however, has such variation because of humans. We were the evolutionary force, creating mutations from inbreeding and artificial selection, which led to different sizes, shapes and behaviours.
There are multiple differences between the grey wolf and the domestic dog. One of the most obvious differences between them is their appearance. The colour of the grey wolf’s coat ranges from grey to black to tawny to white. The domestic dog, however, has all kinds of different coat colours: gold, brindle, liver, off white, peppered, balck, tan, brown etc. Another difference between the two species is their behaviour towards humans. An experiment was undertaken by a man named Adam Miklosi, a canine cognition researcher from Hungary. He was trying to prove that a difference in behaviour between wolves and dogs was due to genetic differences, rather than the environment in which they were raised. He and his team took advantage of a unique situation where thirteen wolves were hand-raised and socialised in human homes, exactly the same as dogs. They performed two tests, both of which were unsolvable, and took notes. In the experiments, only 2 of 7 wolves looked back at the human experimenter for help, compared with 5 of 7 dogs. The dogs also looked back earlier than the wolves did, and for a longer duration. Adam Miklosi and his team came to the conclusion that dogs’ social skills were encoded in their genes (a genetic predisposition). This shows that the grey wolf has no interest in humans, whereas the domestic dog does, and that this is a genetic difference, caused by artificial selection by humans.
A point of view that opposes my own would be one of Charles Darwin’s. He thought that because there is such diversity between dog breeds, there were multiple sources where DNA could have come from. Animals in the Canidae family (a group with wolf-like canids) would be where the DNA would have come from if Darwin’s theory was correct. This means the DNA could have come from wolf, coyote or jackal.
Darwin’s theory is wrong because it has been proven that dog and wolf are almost identical genetically. DNA tests have been run and have come to the conclusion that the domestic dog and the wolf have less than 1% difference in DNA, whereas the DNA difference between the wolf and the coyote is 4%. This means that the domestic dog did indeed come from the grey wolf.
Over 15,000 years ago, there was no such thing as the domestic dog, but after a long process of artificial selection and inbreeding, it has been created. It is hard to believe that over 400 breeds of dog are related to only one animal: the grey wolf. There are many differences between the two animals, but there is no denying that they share nearly identical DNA.

Lizzie's Response

A difference between the gray wolf and the domestic dog are that gray wolves are wild animals which evolved through the process of natural selection, whereas domestic dogs were selectively bred by humans for specific traits. (Humans have an affinity for achieving their idea of ‘perfection’. If they liked the look of a wolf with smaller ears instead of larger, they would choose to domesticate that wolf, and would want its pups to look the same as it.)This difference would not exist without people.
Another difference is the personality and attitude towards people that they have, but there is a lot of debate over whether this is genetic or learnt, because young wolf cubs can easily be brought up to behave exactly like dogs, but once they are a month old, efforts to domesticate them completely are usually fruitless. Once again, this is a difference that revolves around people.
Wolves and dogs look very different as dogs have adapted to (or been adapted to, through the interference of people) different environments and ways of living. The wolves, who didn’t have human transport as a means of travel, weren’t able to cross oceans to get to new places. However, many breeds of dog are genetically close enough to wolves that they are able to breed and produce fertile offspring. This means that they are more compatible than horses and donkeys, or tigers and lions.
Gray wolves look so similar to each other because they have adapted to one environment. Although some circumstances have created sub-breeds (for example, when the wolf population dipped, wolves bred with coyotes, creating the red wolf.) Despite this, gray wolves still exist, because they are good at living where they do. They have long legs to overcome the deep snow that covers most of their habitat, and they are good at retaining body heat. This doesn’t need to change. If a wolf was born with a mutation, for example having short fur, there is a strong chance it wouldn’t survive. Dogs look so different from each other because humans have isolated them from each other by taking them to different places in the world, and because different people like different things as far as pet dogs go, pet dogs bred in Mexico would look completely different to pet dogs in China, not to mention that they had completely different environments to adapt to.

From Wolf to Woof

1 comment:

  1. Wow... I wrote a lot more than Lizzy! Yours is really good btw, Lizzy.