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The Human-Influenced Evolution of Dogs
Seed Magazine ^ | 18 July 2006 | Emily Anthes

Posted on 07/18/2006 9:06:26 AM PDT by PatrickHenry

Thanks to their domestication and favored pet status, dogs have enjoyed a genetic variability known to few other species.

It may be time to revise that old maxim about humans and their canine companions. A man, it seems, is a dog's best friend, and not vice versa.

A paper in the June 29th issue of Genome Research presents evidence suggesting that the domestication of dogs by humans has given rise to the immense diversity of the canine species by allowing otherwise harmful genetic mutations to survive.

"Dogs that would have otherwise died in the wild would have survived because humans would have allowed them to," said Matt Webster, a geneticist at the University of Dublin and one of the study's authors.

The stunning diversity of dogs — Canis lupus familiaris, includes lumbering St. Bernards, sprightly Jack Russell terriers, and graceful greyhounds — has been a source of scientific interest since Darwin, who speculated that these creatures must have descended from several different species. (Scientists now know dogs have a single ancestral species, the gray wolf.)

"Within a single species you have this tremendous range of morphological variation, all this diversity — head shape, body shape, coat color, length — and a tremendous amount of variation in behavior," said Leonid Kruglyak, a geneticist at Princeton University. "Where does all this come from? The parent species, which is the wolf, doesn't show this diversity."

Webster and his colleagues collected and sequenced DNA from the mitochondria of wolf and dog cells. Using this data, they looked for genetic mutations and calculated the rate at which mutations appeared.

Genetic mutations can be divided into two broad categories: nonsynonymous mutations actually change the protein that a stretch of DNA codes for, while synonymous, or silent, mutations do not.

Webster and his colleagues found that the silent mutations occur at similar rates in dogs and wolves, but that nonsynonymous mutations accumulate twice as fast in dogs as they do in wolves. These random changes to proteins are usually harmful, and would have a weakly deleterious effect on dogs and their ability to survive, said Webster.

"That suggests that during dog evolution there's been a relaxation of selective constraint," he said. "These additional changes that have happened during dog evolution have escaped the pressure of natural selection."

Because humans made it easier for domesticated dogs to survive, random genetic mutations that reduced evolutionary fitness — and would have died out in wild dog populations — were able to persist. Furthermore, as humans bred dogs for more desirable traits, they may have exploited these random mutations, accentuating already present variation.

"A lot of the changes over dog evolution would have provided the raw material that humans have used to shape different breeds," Webster said.

The result, then, is the phenomenal diversity in characteristics among different dogs and dog breeds today.

Elaine Ostrander, a geneticist at the National Human Genome Research Institute who worked on the institute's dog genome project, praised Webster's research and its use of mitochondrial DNA.

"For them to focus on mitochondrial DNA was an insightful decision," Ostrander said. "It's been neglected in canine genetics."

Mitochondrial DNA, because it resides outside the cell nucleus, is passed down only from mother to offspring, and it accrues mutations particularly fast. While that might make mitochondrial DNA a natural place to study rates of genetic variation, it's not yet clear whether Webster's findings will apply to the nuclear genome.

"The mitochondrial genome is such a small percentage of the dog genome," said Princeton's Kruglyak. "The interpretations are somewhat speculative."

Nevertheless, he conceded that the researchers' findings and proposed explanation are reasonable, even if not definitive.

"It's difficult to figure out what exactly happened over the last 10,000 years of dog domestication," he said. "It's not clear that any other species has been pushed by artificial human selection to the same extent. There's definitely a very interesting set of questions to be answered."


TOPICS: Culture/Society; Philosophy
KEYWORDS: chatroom; crevolist; dogs; enoughalready; godsgravesglyphs; pavlovian
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This is a thread about evolution. I'm hoping -- perhaps in vain -- that everyone won't pile in to post cutsy pics of your dogs.
1 posted on 07/18/2006 9:06:28 AM PDT by PatrickHenry
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To: VadeRetro; Junior; longshadow; RadioAstronomer; Doctor Stochastic; js1138; Shryke; RightWhale; ...
Evolution Ping

The List-O-Links
A conservative, pro-evolution science list, now with over 380 names.
See the list's explanation, then FReepmail to be added or dropped.
To assist beginners: But it's "just a theory", Evo-Troll's Toolkit,
and How to argue against a scientific theory.

2 posted on 07/18/2006 9:07:54 AM PDT by PatrickHenry (The Enlightenment gave us individual rights, free enterprise, and the theory of evolution.)
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To: PatrickHenry
Dogs that would have otherwise died in the wild would have survived because humans would have allowed them to

As the owner of four chihuahuas I can only say "Amen!"

3 posted on 07/18/2006 9:09:45 AM PDT by white trash redneck (Everything I needed to know about Islam I learned on 9-11-01.)
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To: PatrickHenry
So far it's just another thread about extreme variation within a single species.

For all we know the variation arises out of DNA mythelation and not from genetic change.

In any case, anyone have an idea on which chromosome we'll find the gene that prevents chihuahua dogs from being permanently toilet trained? Those little suckers FORGET.

4 posted on 07/18/2006 9:10:05 AM PDT by muawiyah (-)
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To: PatrickHenry

"that everyone won't pile in to post cutsy pics of your dogs"

That's an invitation to Helen Thomas pics.


5 posted on 07/18/2006 9:11:15 AM PDT by MeanWestTexan (Many at FR would respond to Christ "Darn right, I'll cast the first stone!")
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To: white trash redneck
Dogs that would have otherwise died in the wild

Dogs doing jobs cats don't want to do....

6 posted on 07/18/2006 9:12:28 AM PDT by llevrok (Born a ham and never cured.)
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To: PatrickHenry
Genetic diversity, in this instance, seems to be result of a series of interventions by a series of intelligent designers.

Good info.

7 posted on 07/18/2006 9:12:43 AM PDT by ClearCase_guy ("He hits me, he cries, he runs to the court and sues me.")
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To: PatrickHenry
But they're still wolves.

No, wait...

8 posted on 07/18/2006 9:12:56 AM PDT by Junior (Identical fecal matter, alternate diurnal period)
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To: PatrickHenry

I don't know if the diversity of dogs represents evolution or selective breeding from man, but I have known dogs and cats to possess individual, unique personality traits and intelligence that are far beyond what the Bible calls voided minds of brute beasts.


9 posted on 07/18/2006 9:13:02 AM PDT by sully777 (You have flies in your eyes--Catch-22)
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To: muawiyah
So far it's just another thread about extreme variation within a single species.

That's exactly how speciation begins. Quite in accordance with the theory of evolution.

10 posted on 07/18/2006 9:13:31 AM PDT by PatrickHenry (The Enlightenment gave us individual rights, free enterprise, and the theory of evolution.)
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To: PatrickHenry

The diversity of dog breeds can be attributed to the 48 pair of chromosomes in comparison to the 22 pair found in humans.


11 posted on 07/18/2006 9:14:31 AM PDT by colorcountry ( Run with scissors???? I can barely jog my memory)
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To: muawiyah
So far it's just another thread about extreme variation within a single species. For all we know the variation arises out of DNA mythelation and not from genetic change.

From the article:

"Within a single species you have this tremendous range of morphological variation, all this diversity — head shape, body shape, coat color, length — and a tremendous amount of variation in behavior," said Leonid Kruglyak, a geneticist at Princeton University. "Where does all this come from? The parent species, which is the wolf, doesn't show this diversity."

12 posted on 07/18/2006 9:15:02 AM PDT by Lurking Libertarian (Non sub homine, sed sub Deo et lege)
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To: PatrickHenry
This isn't merely evolution; it's intelligently designed evolution. :-)
13 posted on 07/18/2006 9:16:50 AM PDT by two134711
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To: Junior
Photobucket - Video and Image Hosting
14 posted on 07/18/2006 9:16:58 AM PDT by MarkeyD (The patriotism of the New York Times = The humanity of an Islamic terrorist.)
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To: muawiyah

"DNA mythelation"


....OK, I give up. What is this?


15 posted on 07/18/2006 9:19:04 AM PDT by 2nsdammit (By definition it's hard to get suicide bombers with experience.)
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To: PatrickHenry

Very interesting article but I would note that humans are just as much a part of nature as are dogs.


16 posted on 07/18/2006 9:19:08 AM PDT by AntiGuv ("..I do things for political expediency.." - Sen. John McCain on FOX News)
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To: Lurking Libertarian
The parent species, which is the wolf, doesn't show this diversity.

But humans probably interbred wolves with coyotes, dingos, foxes, and other canine species.

17 posted on 07/18/2006 9:19:57 AM PDT by lesser_satan (EKTHELTHIOR!!!)
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To: MarkeyD
Genetic mutation keeps our pup from drowning in the mud thanks to those webbed feet

18 posted on 07/18/2006 9:20:41 AM PDT by f zero
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To: lesser_satan

WTF?


19 posted on 07/18/2006 9:20:50 AM PDT by MarkeyD (The patriotism of the New York Times = The humanity of an Islamic terrorist.)
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To: PatrickHenry

My fat, fluffy, spoiled kitty-cat couldn't survive in the wild, either. I think she'd starve to death rather than dine on mice, waiting for someone to bring her the kibble.


20 posted on 07/18/2006 9:21:30 AM PDT by CobaltBlue (Extremism in the defense of liberty is no vice. Moderation in the pursuit of justice is no virtue.)
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To: lesser_satan
But humans probably interbred wolves with coyotes, dingos, foxes, and other canine species.

I don't think the DNA evidence bears that out, but I'm not an expert in this.

21 posted on 07/18/2006 9:21:43 AM PDT by Lurking Libertarian (Non sub homine, sed sub Deo et lege)
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To: PatrickHenry

I've often used the variety found within dogs and the role of selective breeding in evolution discussions. Frankly, given the advancements in medicine I see the human race over the next three generations getting equal diversity (if it hasn't already!). Folk who wouldn't have survived or been able to pass on their genes 20 years ago, now can. That is going to massively widen the gene pool of the human race.

And in my opinion that's a good thing....The fewer variations found within a species, the closer that species is to extinction.

All according to my untrained pop science of course....


22 posted on 07/18/2006 9:22:18 AM PDT by Brit_Guy
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To: f zero

If you haven't, you should read "Marley and Me".


23 posted on 07/18/2006 9:22:33 AM PDT by MarkeyD (The patriotism of the New York Times = The humanity of an Islamic terrorist.)
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To: Junior
But they're still wolves.
No, wait...

Actually, they still are...that's why there are still dog/wolf hybrids.

Parent taxa

Genus Canis (dogs, jackals, and wolves)
Species Canis lupus (gray wolf)
Subspecies Canis lupus dingo (dingo)
Subspecies Canis lupus familiaris (dog)

24 posted on 07/18/2006 9:22:59 AM PDT by omegatoo
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To: Dysart

this should be fun later mark


25 posted on 07/18/2006 9:23:09 AM PDT by Dysart
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To: PatrickHenry

But isn't evolution a fairy tale for Atheists?


26 posted on 07/18/2006 9:23:19 AM PDT by bigcat32
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To: Brit_Guy
That is going to massively widen the gene pool of the human race.

If so, then the gene pool will sharply narrow again once parents can select the traits of their children, since the range of desirable traits is relatively narrow, and narrower than the current range of traits.

27 posted on 07/18/2006 9:24:35 AM PDT by AntiGuv ("..I do things for political expediency.." - Sen. John McCain on FOX News)
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To: CobaltBlue
I think she'd starve to death rather than dine on mice

Mine catches the mice, brings them inside, drops them in the food dish and then eats the dry food.

28 posted on 07/18/2006 9:25:35 AM PDT by palmer (Money problems do not come from a lack of money, but from living an excessive, unrealistic lifestyle)
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To: bigcat32

That's like asking: Why isn't the sun at the bottom of the Pacific?


29 posted on 07/18/2006 9:26:00 AM PDT by AntiGuv ("..I do things for political expediency.." - Sen. John McCain on FOX News)
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To: Lurking Libertarian
Chelsea?

I know, I'm bad.
30 posted on 07/18/2006 9:27:05 AM PDT by MarkeyD (The patriotism of the New York Times = The humanity of an Islamic terrorist.)
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To: ClearCase_guy

"Genetic diversity, in this instance, seems to be result of a series of interventions by a series of intelligent designers."

Humans did not cause any of the genetic variation; they just selected which ones they wanted after the fact.


31 posted on 07/18/2006 9:27:42 AM PDT by CarolinaGuitarman (Gas up your tanks!!)
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To: bigcat32

"But isn't evolution a fairy tale for Atheists?"

No.


32 posted on 07/18/2006 9:28:44 AM PDT by CarolinaGuitarman (Gas up your tanks!!)
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To: PatrickHenry

Thanks for the ping!


33 posted on 07/18/2006 9:29:05 AM PDT by Alamo-Girl
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To: MarkeyD

Re-read my post. I wasn't implying that humans were breeding with the canines.


34 posted on 07/18/2006 9:29:25 AM PDT by lesser_satan (EKTHELTHIOR!!!)
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To: ClearCase_guy

I wonder if our canine friends have conversations like this:

Spot: You know, I have a theory that our human masters may have intervened in our development. That our current condition may have been the result of an "intelligent design," if you will.

Rover: You're an idiot. You're ignoring the mountains of overwhelming scientific evidence that we just evolved completely by ourselves. What are you trying to do - force us all to pray to your human gods? Throw us back into the doggie dark ages before pet salons and canine massages? Your stupid, idiotic ramblings are an insult. Where did you come up with this nonsense? While you were chasing your tail? Did I mention that you're an idiot?


35 posted on 07/18/2006 9:31:24 AM PDT by Shadowfax
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To: AntiGuv

Silly... That only happens at night.


36 posted on 07/18/2006 9:32:31 AM PDT by Redcloak (Speak softly and wear a loud shirt.)
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To: lesser_satan

Yep, sorry.


37 posted on 07/18/2006 9:32:54 AM PDT by MarkeyD (The patriotism of the New York Times = The humanity of an Islamic terrorist.)
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To: CobaltBlue
My fat, fluffy, spoiled kitty-cat couldn't survive in the wild, either. I think she'd starve to death rather than dine on mice, waiting for someone to bring her the kibble.

Cats only hunt and kill if their mother teaches them.

The survival rate of feral dogs is about five percent. (The percentage that lives long enough to breed)

38 posted on 07/18/2006 9:34:18 AM PDT by js1138 (Well I say there are some things we don't want to know! Important things!")
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To: PatrickHenry
"A lot of the changes over dog evolution would have provided the raw material that humans have used to shape different breeds," Webster said.

Then why didn't they shape them to keep quiet in the middle of the night and let me sleep?

39 posted on 07/18/2006 9:34:29 AM PDT by bankwalker (An accusation is often a subconscious confession.)
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To: muawiyah
"...anyone have an idea on which chromosome we'll find the gene that prevents chihuahua dogs from being permanently toilet trained? Those little suckers FORGET."

They don't forget. They just have an odd sense of humor!
40 posted on 07/18/2006 9:36:29 AM PDT by LIConFem (It is by will alone I set my mind in motion...)
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To: Lurking Libertarian

Details, details.


41 posted on 07/18/2006 9:36:37 AM PDT by vpintheak (All other ground is sinking sand.)
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To: MarkeyD
What I want to know is, whose hand is wrapped around that chihuahua? Is it Reptoidman?


42 posted on 07/18/2006 9:40:22 AM PDT by Defiant (Restraint is not weakness, it is reasoned application of a moral code. There are limits to restraint)
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To: Defiant

Since Chihuahua's come from Mexico, I'd say it is probably the chupacabra.


43 posted on 07/18/2006 9:44:29 AM PDT by MarkeyD (The patriotism of the New York Times = The humanity of an Islamic terrorist.)
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To: PatrickHenry

Humans have successfully manipulated dogs' genetics until the dogs have us just where they want us.


44 posted on 07/18/2006 9:50:00 AM PDT by pabianice
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To: muawiyah

Chihuahua's don't forget, they are just on a shorter schedule than bigger dogs. Also those tiny tiny bladders might have something to do with it.


45 posted on 07/18/2006 9:56:16 AM PDT by Ditter
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To: Defiant


Chupacabra
46 posted on 07/18/2006 9:56:53 AM PDT by MarkeyD (The patriotism of the New York Times = The humanity of an Islamic terrorist.)
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To: Brit_Guy
advancements in medicine

Socialism has an even bigger impact on human diversity. It broadens the gene-pool, mostly in undesirable directions, while jail serves to fine tune it. War's role in human evolution is as a big reset button, bringing the gene pool back into a very narrow range. It's why humans are remarkably the same the world over, and why the Neanderthals no longer exist.

47 posted on 07/18/2006 9:57:19 AM PDT by Reeses
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To: PatrickHenry

And then, sometimes, there doesn't appear to be any variation at all ~ to wit, all kinds of insects on trees in the Amazon.


48 posted on 07/18/2006 9:57:31 AM PDT by muawiyah (-)
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To: PatrickHenry
The Human-Influenced Evolution of Dogs

oxymoron alert.

49 posted on 07/18/2006 9:58:05 AM PDT by DungeonMaster (More and more churches are nada scriptura.)
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To: Lurking Libertarian

What I said.


50 posted on 07/18/2006 9:58:15 AM PDT by muawiyah (-)
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