Dog genome research progress has been fairly slow, partly for economic reasons, but partly, I suspect, because dogs aren't really that variable, strange as it may seem. Without breeding, dogs in the tropics seem to wind up medium size, short-haired, and yellowish, reddish, or brownish.Dog genes that code for such signature pet traits as the furrowed skin of the Shar-Pei have been identified in a study that shows how centuries of breeding gave rise to 400 kinds of domestic dogs.
Researchers analyzed the genes of 275 dogs in 10 breeds to see how breeding practices have altered their DNA, the hereditary template in their cells. The results, reported last week in the Proceedings of the National Academy of Sciences, show that some conspicuous physical traits, or phenotypes, such as height and coat color, can be traced to particular genes of beagles, border collies, dachshunds and poodles, among other breeds.
"When you have a Chihuahua that's nine inches tall and a Great Dane that is seven feet tall, that can be traced back to IGF1," the gene that influences dog size, said Joshua Akey, a geneticist at the University of Washington in Seattle who was the paper's lead author.
Understanding how breeding leads to artificial selection of some doggy DNA can clarify the way genes give rise to appearance and behavior in other species, the researchers said. Such knowledge "holds considerable promise for providing unique insights into the genetic basis of heritable variation in humans," they wrote.
Dogs are "a great system for understanding how genetic variation influences how individuals in a population act differently, look different and have different susceptibilities to disease," Akey said in a telephone interview.
Domesticated dogs have been bred for more than 14,000 years, the report said. The strict form of selective breeding used today to turn out desired characteristics in the animals is a more recent phenomenon.
"Most dog breeds were formed in the last 500 to 1,000 years, a relatively short time frame in terms of evolution," Akey said.
Today there are more than 400 genetically distinct breeds of domestic dog, yet "relatively little progress has been made on systematically identifying which regions of the canine genome have been influenced by selective breeding during the natural history of the dog," the study said.
My hunch is that genetic diversity in dogs will prove to be narrow but deep, focusing on a small number of genes that vary sharply, whereas genetic diversity among humans will prove broader but shallower than among dogs, involving more genes than among dog breeds, but not as sharply defined.
My published articles are archived at iSteve.com -- Steve Sailer
Given the geographic isolation factor and the time of seperation, there is most certainly more genetic difference between Icelanders and Australian aboriginies, than there is between Great Danes and Yorkies.
ReplyDeleteBut dogs in the cold turn into bears.
ReplyDeleteso Kaitlin my friend from the dog park is in the field of 'epigenetics'. you're going to love this. think of DNA as a hose carrying info and it is wrapped with a wire ie, environmental stuff, etc. now go here for a real explanation; sciencedaily.com/releases/2009/04/1090401181447
ReplyDeleteThere's no such thing as dog "breeds" because intermediate examples exist: a pitbull is the same as a border collie except for the way it was raised and border collies are smarter and have weaker jaws only because they were raised differently than the pitbulls.
ReplyDeleteIn fact there are no such things as "dogs" because they can interbreed with wolves and produce intermediate examples. Each is a unique example of something special and can't be categorized in any way. And they haven't evolved or changed at all for 50,000 years because that's impossible.
I think you're right about dogs being more similar than one would normally suspect.
ReplyDeleteAbout 10% of the human brain is devoted to vision. We see various dogs breeds and they look different. But an analogous 10% of a dog's brain is devoted to smell. They recognize each other as being the same because they smell the same. They don't care all that much about how they look.
Horizon, the BBC's flagship popular science programme, recently aired a very interesting episode, The Secret Life of the Dog.
ReplyDeleteI think the so-called Pariah dogs are cute. It is a shame the way dogs are treated in most of the world. I wonder why it is mostly people of European origin that keep pet dogs and treat them well. It is not just about wealth or IQ, that is for certain. In Taiwan, for example, there are a lot of stray dogs that are treated very badly. They have weird superstitions about black dogs with white paws being bad luck.
ReplyDeleteThere are, however, some Taiwanese people who are trying to rescue dogs. I know of someone in Vancouver who adopted a dog from Taiwan. Here is one rescue organization:
http://stray-dogs.org/
Skeptic editor Frank Miele wrote an interesting piece on canine research and possible comparisons with human races.
ReplyDelete"Dog breeds provide the classic case study of within-species differentiation. Those who would dismiss race and race differences regularly point out that DNA differences between races are minimal. But , as Vincent Sarich demonstrated in Race: The Reality of Human Differences (pp. 170 – 173) human racial differences in morphology are greater than in any non-domesticated species. They are around ten times the difference between the sexes within each race and larger than the differences that distinguish the two species of chimpanzee. Despite minimal genetic differences, human physical racial differences are clearly observable.
Likewise for dogs. But only recently has genetic analysis been able to distinguish between breeds—or even between dogs and wolves.
All the differences in body shape, size, color, internal chemistry, and behavior between the hundreds of breeds recognized by the American Kennel Club, the Kennel Club UK, and the Fédération Cynologique Internationale (the World Canine Federation) are based on very few genes.
But while it's OK to talk about differences among dog breeds, not so for human races. Unfortunately, this has been true even in scientific circles. And that in itself is instructive."
http://www.vdare.com/misc/080325_miele.htm
About 10% of the human brain is devoted to vision. We see various dogs breeds and they look different. But an analogous 10% of a dog's brain is devoted to smell. They recognize each other as being the same because they smell the same. They don't care all that much about how they look.
ReplyDeleteThat's an interesting point. I never thought of it this way but it seems to make sense. A tiny Pomeranian interacting with say, an Afghan hound or a Boxer, will certainly act as if they recognize each other on some level despite the big differences in physical appearance, morphology. Much different compared to how they interact with cats and other animals.
Also, fur color is a major component of how people perceive the great phenotypic diversity among dogs. Dogs are colorblind, so this would be less salient to them.
ReplyDeleteIn fact there are no such things as "dogs" because they can interbreed with wolves and produce intermediate examples.
ReplyDeleteOkay, adopt a wolf for your young ones next time.
http://www.ft.com/cms/s/2/628a8500-ff1c-11de-a677-00144feab49a.html
MSM (paper) Trained Liberal said...
ReplyDeleteThere's no such thing as dog "breeds" because intermediate examples exist...
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Exactly! My Chihuahua, Hugie, certainly acts as if he were a pitbull. Hugie thinks he can fight of a pitbull with one paw tied behind his back because breeds are just a social construct and all dogs are equal.
Albertosaurus:
ReplyDeleteAbout 10% of the human brain is devoted to vision. We see various dogs breeds and they look different.
That's because dog breeds are bred mostly for appearance - to look different from each other.
An interesting example of selective breeding are the (in)famous "Belgian Blue" bulls. They are bred to be muscular, by selective breeding only. They are the most muscular cows your mind can imagine.
ReplyDeletehttp://www.simnet.is/japan/belgianblue.jpg
Look (!) at the picture of that "bodybuilder" cow. He's basically a representative sample of what breeding for muscularity can do in a short time.
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Now think of what breeding for athletic prowess could do if only the biggest, strongest, most athletic men were generally chosen by females would do to a race of people.............oh wait, we see that in ghettos all the time don't we?
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Now think of what community leaders could do if they attempted to mate men and women who excel at various subjects (math brains and literary brains) together for a thousand years or so......oh wait, one group of people have "kinda" done that, haven't they?
We have no idea what true human potential is. The world bench press record is now over 1000 lbs (Ryan Kennelly--a white American). Its hard to say what the upper limit for people is.
Although most dogs today are bred specifically for appearance, most dogs breeds were originally bred for specific beahvioral traits. Generations of selective breeding emphasized different traits such as herding, trailing, retreiving, pointing, guarding, etc. All of these traits are present in dogs to some degree, but different breeds developed as people selectively bred dogs possessing the desired traits to a higher degree than others.
ReplyDeleteAlthough it cannot be said that any one breed of dogs is better than others overall, certain breeds are better than others for certain tasks. For example, most shepherd breeds would be hopeless at hunting, while most hounds would be of no value in herding livestock. Each of the specific hound or shepherd breeds was bred for a specific purpose. Curs, on the other hand, were bred for both hunting and herding. A cur is generally not as good as hunter as a hound or as good at herding livestock as a shepherd, but does a reasonably good job at both.
On my farm there is a bird which imitates the yelp that my terrier makes when chasing a rabbit.
ReplyDeleteNo doubt being a competitive male thrush he figures he can do a better job. He is known as the "Jack Russell in pursuit bird".
He or his friend will also have a go at imitating the truck beeping when it goes backwards..."the reversing Nissan bird"
Will be interesting when truck and dog have passed on whether this avian meme endures in the bailiwick.
Farmer F
"albertosaurus said...
ReplyDeleteI think you're right about dogs being more similar than one would normally suspect.
About 10% of the human brain is devoted to vision. We see various dogs breeds and they look different. But an analogous 10% of a dog's brain is devoted to smell. They recognize each other as being the same because they smell the same. They don't care all that much about how they look."
It's funny, I thought of the exact same point with reference to human racial differences. If people had a dog-like sense of smell we would have a very different view of human biodiversity; as it is, we focus on things like size, skin color and facial features.
But the other thing about dogs is that whenever anybody talks about "the extraordinary variety of dog breeds" they pretty much bring up those ugly little yap dogs - terriers and so forth - and then great danes. Most of the dogs I actually see look sort of like small to midsized wolves, apart from their coats.
Darwin preferred pigeon breeders, who selected for traits from color to feather-type to speed, with results apparent 3 - 4 times as rapidly as dog-breeders'.
ReplyDeleteEvolution is a highly statistical result of adaptional or selected growth and change. "Pigeon fanciers" and dog-breeders have little use for Six Day creation-myth chronologies.
albertosaurus said that "... 10% of a dog's brain is devoted to smell. They recognize each other as being the same because they smell the same. They don't care all that much about how they look."
ReplyDeleteI'm intrigued but out of my depth, given my olefactory limitations
perhaps dogs can make sharp distinctions based on smell, comparable to humans using sight to make distinctions?
any evidence to support this?