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Kibble for Thought: Dog diversity prompts new evolution theory
Science News ^ | 18 December 2004 | Christen Brownlee

Posted on 12/21/2004 8:45:42 AM PST by PatrickHenry

The wide range of variety in domesticated dogs — from the petite Chihuahua to the monstrous mastiff — has powered a new view of what drives evolution.

Scientists have long known that the evolutionary changes that alter a species' appearance or create new species frequently occur in rapid bursts. One widely accepted theory holds that any evolutionary change results from a random switch of a single genetic unit within DNA.

These single-point mutations occur in about 1 out of every 100 million DNA sites each generation. This frequency is too low to cause rapid evolutionary change, assert John W. Fondon and Harold R. Garner, biochemists at the University of Texas Southwestern Medical Center at Dallas.

While examining human-genome data, Fondon found that small segments of repeated DNA sequences, called tandem repeat sequences, are frequently present in genes that control how an animal develops into its final appearance. Unlike single-point mutations, tandem repeat mutations occur when a cell's machinery for copying DNA makes a mistake and inserts a different number of sequence copies.

Such mistakes, which happen 100,000 times as often as single-point mutations, could alter an organism's appearance or function for successive generations.

"I was stunned by what I found," says Fondon. "It occurred to me that this might be a nifty way for [organisms] to evolve very rapidly."

To evaluate this hypothesis, Fondon and Garner looked for tandem repeat sequences in 92 breeds of domesticated dogs. For example, they examined a gene that determines nose length. They found that the number of times a particular sequence is repeated correlates strongly with whether a breed has a short or long muzzle.

Many researchers explain dog-breed diversity as the emergence of hidden traits in the genome. However, says Fondon, a more likely scenario is that genetic mutations occur in dogs at a high rate.

By comparing skulls of dogs over decades, Fondon and Garner found significant and swift changes in some breeds' appearances. For example, between the 1930s and today, purebred bull terriers developed longer, more down-turned noses.

Moreover, the researchers found more variation in tandem-sequence repeat lengths among dogs than they found in the DNA of wolves and coyotes.

These results suggest that dogs have experienced significantly higher rates of tandem repeat mutations than the related species have, says Fondon. Because tandem-repeat sequences litter the genes that control the developmental plan in many species, Fondon suggests that mutations in these regions could have a strong bearing on evolution.

"As a new finding about the biology and genetics of dogs, I'm all for it. But in terms of applying this to [evolution in general], I think there's a question mark," says Sean Carroll, an evolutionary geneticist at the University of Wisconsin–Madison.

Carroll notes that because dog owners have coddled their companions over the centuries, mutations that would have killed wild animals may have persisted in the gene pool of domestic dogs. Because domestication diverges from a standard model of evolution, he says, further experiments are necessary to add weight to Fondon and Garner's theory.


TOPICS: Culture/Society; Miscellaneous; Philosophy
KEYWORDS: agriculture; animalhusbandry; crevolist; darwin; dietandcuisine; dog; dogs; domestication; evolution; godsgravesglyphs; helixmakemineadouble; huntergatherers; morphology
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To: Red Badger

Pygmies and Zulus could still meet in the middle, so to speak.

The definition of "species" is not willingness.

My wife's little yippy dog mates with a soccer ball all day long. They ain't the same species (although I always have an urge to kick both).

The prerequisite is: "Can they mate without artificial help?" If so, go to next test. If not, then not the same species.

Ergo, little yippy dogs and really big dogs are no longer the same species.


101 posted on 12/21/2004 10:17:26 AM PST by MeanWestTexan
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To: Red Badger

My mutt is half border collie, half purebred miniature Lab.

Just about the harriest beast I ever met, I found one of his hairs on the floor and it measured 14 inches.

My neighbor insists my hound is smarter and more likeable than alot of people he meets. At 13, he's doing fine.


102 posted on 12/21/2004 10:18:18 AM PST by djf
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To: Modernman

"Interesting, but terribly disturbing."

Yep.


103 posted on 12/21/2004 10:18:48 AM PST by MeanWestTexan
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To: PatrickHenry
As the owner of both a dog and a cat, I've often marveled at how much easier their species would have survived if they could only have developed some ability to talk. If gives any animal a tremendous advantage in terms of survival that I don't understand why all animals didn't "evolve" this capability.
104 posted on 12/21/2004 10:22:57 AM PST by finnigan2
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To: orionblamblam
I guess Carl Sagan murmuring "beeeeg baaaang beeeellions" is far more sensible? Faith is not ever going to be entirely sensible, but there is plenty to laugh at, and with high uproar and delight, when the Hans Vavink Protocol gets a head of steam. Und zen! hans waving frantically in air Beelyons of yars, zey happen! Und, vee gets ze eyes, ze ears, ze intellect, ze new and improved fruit flies!
105 posted on 12/21/2004 10:23:39 AM PST by Mamzelle (He's scared of me...! Honest, I won't hurt him!)
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To: Mamzelle

WFT are you babbling about? While the origins and specifics of the Big Bang might be more than a little hazy, the evidence for it is pretty abundant (look up the work of Hubble). The evidence for evolution is even more abundant. We're now finding the genetic mechanisms that let it happen; we've understood the basic cause-and-effect principles of nature that drive it, and the fossils show the trail of it.

Wave your hands all you want. Rant all you want. Creationists will occupy the same hallowed ground as the hollow-earthers in the history books. If they persist, they will drag their religion down with them.


106 posted on 12/21/2004 10:28:20 AM PST by orionblamblam
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To: MeanWestTexan
Ergo, little yippy dogs and really big dogs are no longer the same species.

As a criterion of whether or not two creatures are of a different species, I believe the ability to mate refers to the genetic ability, not the physical ability, meaning can sperm from the one successfully fertilize the egg of the other (or however else the two organisms might reproduce). In the case of the dogs, the answer is clearly yes. Just because the "equipment" of the mastiff may be too large to fit that of the chihuahua, it doesn't make them different species. Besides, I'm willing to bet that if you left a male chihuahua and a female mastiff in a room for long enough, the chihuahua would find a way to make it happen.
107 posted on 12/21/2004 10:32:17 AM PST by fr_freak
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To: finnigan2

Some cats do behave strangely. I had a couple watch "Forever Amber" on the television a few years ago. I thought that was strange because the both hated the book.


108 posted on 12/21/2004 10:34:05 AM PST by Doctor Stochastic (Vegetabilisch = chaotisch is der Charakter der Modernen. - Friedrich Schlegel)
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To: orionblamblam
You know, you evolutionists ought to evolve a sense of humor. "Hans Vavink" was what I picked up in a physics class once. The professor actually had a funny bone in his genetic makeup--he said, "When the theory starts falling apart, employ the Hans Vavink protocol to get you out of jam". When we looked at him questioningly, he started waving his hands in the air. I see this protocol applied in many discussions in FR conscerning the origin of mankind.

When your fruit flies won't evolve, just call the one who notices "superstitious"...

109 posted on 12/21/2004 10:34:59 AM PST by Mamzelle (He's scared of me...! Honest, I won't hurt him!)
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To: finnigan2
They do talk, to each other. Cats and dogs have a well developed verbal and non verbal language to communicate with each other. The submissive tail posture, howling, etc. It is simplistic by our standards, but it is there. Not to mention they have a whole media that we are relatively blind to, scent.

Cats and Dogs both occupy the top tiers of the food chain for their niche. What advantage would they gain by refining their language more? They are already top predators. There probably wasn't any real competition for them until we came along. IMO
110 posted on 12/21/2004 10:40:22 AM PST by Wisconsin155 (newbie)
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To: Rodney King
My ridgeless RR was free. The breeder was going to put him to sleep but my brother (a vet) talked him out of it by telling him he would find homes for the ridgeless ones. Naturally he called his sister who never turned down the offer of a free dog. Best deal I ever made.
111 posted on 12/21/2004 10:42:31 AM PST by Ditter
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To: orionblamblam
We're now finding the genetic mechanisms that let it happen; we've understood the basic cause-and-effect principles of nature that drive it, and the fossils show the trail of it.

Maaaan quit yippin'. Your theory has more holes than swiss cheese.

================

The Five Crises in Evolutionary Theory, by Dr. Ray Bohlin

Link

1. The unsubstantiation of a Darwinian mechanism of evolution

2. The total failure of origin of life studies to produce a workable model

3. The inability of evolutionary mechanism to explain the origin of complex adaptations

4. The bankruptcy of the blind watchmaker hypothesis

5. The biological evidence that the rule in nature is morphological stability over time and not constant change.

Raymond G. Bohlin is a graduate of the University of Illinois (B.S., zoology), North Texas State University (M.S., population genetics), and the University of Texas at Dallas (M.S., Ph.D., molecular biology)

===========================

No Speciation

Joseph Boxhorn, author of the talk-origins 'FAQ' on Speciation, makes a bold promise from the outset in his choice of title for his paper: 'Observed Instances of Speciation.' Any rational person visiting this site will naturally expect to find a list of cases where scientists, under controlled experimental conditions, have actually observed the process of speciation taking place.

However, anyone expecting to find such a list in Boxhorn's 'FAQ' is due for a major disappointment. It is true that Boxhorn does list a number of scientific observations, yet -- almost incredibly -- not a single one of these observations can be described as 'speciation' in the Darwinian sense, except by employing the kind of Double-Think used by officials at George Orwell's Ministry of Truth.

====================

Micro vs. Macro

Proponents of evolution often attempt to discredit creation by pointing to occurrences of microevolution, such as speciation, adaptation, etc. To the evolutionist, microevolution is vindication for their belief in the much larger macroevolution. Their belief is that if these microevolutionary changes have enough time to accumulate, then eventually this will lead to a macroevolutionary change. And therefore, in their way of thinking, if microevolution is a well established fact, macroevolution must logically be an established fact as well.

====================

Intelligent Design — Intro

112 posted on 12/21/2004 10:45:05 AM PST by Michael_Michaelangelo (The best theory is not ipso facto a good theory.)
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To: MeanWestTexan
The prerequisite is: "Can they mate without artificial help?" If so, go to next test. If not, then not the same species.

I think you should probably rethink your test with special consideration given to Pfizer.

113 posted on 12/21/2004 10:46:21 AM PST by jwalsh07
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To: Mamzelle

One of my sons said he could breathe underwater, and the others thought he was evolving, but we concluded that he's really a space alien.


114 posted on 12/21/2004 10:48:54 AM PST by Tax-chick (Jesus is the reason for the season which begins at sundown on December 24.)
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To: jwalsh07
re: The prerequisite is: "Can they mate without artificial help?" )))

Does this mean Viagra has brought about a new human species? I mean, talk about your artificial help...

115 posted on 12/21/2004 10:50:43 AM PST by Mamzelle (He's scared of me...! Honest, I won't hurt him!)
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To: Ditter
Best deal I ever made.

Sounds like it!

116 posted on 12/21/2004 10:51:53 AM PST by Rodney King (No, we can't all just get along.)
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To: jwalsh07

LOL. But, alas, not my test. It's in every Bio 101 text book.

And, with the horse answer above, in normal conditions, humans can normally mate without the help of little pills, so they are the same species, even if help is sometimes used.

If not, I would be of a different species than a democrat, as I would not consider mating with one without the help of tequila.


117 posted on 12/21/2004 10:53:20 AM PST by MeanWestTexan
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To: Mamzelle
I would think naive would be a better description.

Now to address your strawman argument about the fruit fly. Evolution is a gradual change. You can not wait around for it to happen in our timeline and then say, "well didn't happen, your wrong". The fossil record is the only way to witness the changes. There are plenty of transitional fossils that prove the point, if you bothered to look it up. But again, just because evolution is true, does not prove or disprove God. Why you creationist types continue to fabricate unscientific babble, simply to preserve your precious dogma, is beyond my understanding
118 posted on 12/21/2004 10:55:45 AM PST by Wisconsin155 (newbie)
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To: PatrickHenry

So...this has something to do with Typing Dogs......?


119 posted on 12/21/2004 10:56:16 AM PST by PoorMuttly ("The right of the People to be Muttly shall not be infringed,")
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To: orionblamblam
Creationists will occupy the same hallowed ground as the hollow-earthers in the history books. If they persist, they will drag their religion down with them.

That's a silly statement. How can someone bring down his religion by believing in it?

The evidence for evolution is far from conclusive. In fact, research in the field these days seems to punch as many holes in the theory as it does patch them. For me, the greatest flaw in the theory is that, as an explanation for how existing life got on this planet, it necessarily points to spontaneous generation of life. Now, I know that most proponents of evolutionary theory say that spontaneous generation isn't part of the theory, that it only covers what happens to organisms once they already existed, but unless a theory accompanies evolution to explain that, evolution is starkly incomplete.

And by the way, the idea of spontaneous generation of life, to me, is a ridiculous concept. I won't go as far as to say that it is completely impossible, but I would find the possibility of a Creator to be far more likely.
120 posted on 12/21/2004 11:00:17 AM PST by fr_freak
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