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Researchers Trace Evolution to Relatively Simple Genetic Changes
Howard Hughes Medical Institute ^ | 25 Narcg 2005 | Staff

Posted on 05/31/2005 12:03:06 PM PDT by PatrickHenry

In a stunning example of evolution at work, scientists have now found that changes in a single gene can produce major changes in the skeletal armor of fish living in the wild.

The surprising results, announced in the March 25, 2005, issue of journal Science, bring new data to long-standing debates about how evolution occurs in natural habitats.

“Our motivation is to try to understand how new animal types evolve in nature,” said molecular geneticist David M. Kingsley, a Howard Hughes Medical Institute investigator at the Stanford University School of Medicine. “People have been interested in whether a few genes are involved, or whether changes in many different genes are required to produce major changes in wild populations.”

The answer, based on new research, is that evolution can occur quickly, with just a few genes changing slightly, allowing newcomers to adapt and populate new and different environments.

In collaboration with zoologist Dolph Schluter, at the University of British Columbia, Vancouver, Canada, and Rick Myers and colleagues at Stanford, Kingsley and graduate student Pamela F. Colosimo focused on a well-studied little fish called the stickleback. The fish — with three bony spines poking up from their backs — live both in the seas and in coastal fresh water habitats all around the northern hemisphere.


Wild populations of stickleback fish have evolved major changes in bony armor styles (shaded) in marine and freshwater environments. New research shows that this evolutionary shift occurs over and over again by increasing the frequency of a rare genetic variant in a single gene.

Sticklebacks are enormously varied, so much so that in the 19th century naturalists had counted about 50 different species. But since then, biologists have realized most populations are recent descendants of marine sticklebacks. Marine fish colonized new freshwater lakes and streams when the last ice age ended 10,000 to 15,000 years ago. Then they evolved along separate paths, each adapting to the unique environments created by large scale climate change.

“There are really dramatic morphological and physiological adaptations” to the new environments, Kingsley said.

For example, “sticklebacks vary in size and color, reproductive behavior, in skeletal morphology, in jaws and teeth, in the ability to tolerate salt and different temperatures at different latitudes,” he said.

Kingsley, Schluter and their co-workers picked one trait — the fish's armor plating — on which to focus intense research, using the armor as a marker to see how evolution occurred. Sticklebacks that still live in the oceans are virtually covered, from head to tail, with bony plates that offer protection. In contrast, some freshwater sticklebacks have evolved to have almost no body armor.

“It's rather like a military decision, to be either heavily armored and slow, or to be lightly armored and fast,” Kingsley said. “Now, in countless lakes and streams around the world these low-armored types have evolved over and over again. It's one of the oldest and most characteristic differences between stickleback forms. It's a dramatic change: a row of 35 armor plates turning into a small handful of plates - or even no plates at all.”

Using genetic crosses between armored and unarmored fish from wild populations, the research team found that one gene is what makes the difference.

“Now, for the first time, we've been able to identify the actual gene that is controlling this trait,” the armor-plating on the stickleback, Kingsley said

The gene they identified is called Eda, originally named after a human genetic disorder associated with the ectodysplasin pathway, an important part of the embryonic development process. The human disorder, one of the earliest ones studied, is called ectodermal dysplasia.

“It's a famous old syndrome,” Kingsley said. “Charles Darwin talked about it. It's a simple Mendelian trait that controls formation of hair, teeth and sweat glands. Darwin talked about `the toothless men of Sind,' a pedigree (in India) that was striking because many of the men were missing their hair, had very few teeth, and couldn't sweat in hot weather. It's a very unusual constellation of symptoms, and is passed as a unit through families.”

Research had already shown that the Eda gene makes a protein, a signaling molecule called ectodermal dysplasin. This molecule is expressed in ectodermal tissue during development and instructs certain cells to form teeth, hair and sweat glands. It also seems to control the shape of - bones in the forehead and nose.

Now, Kingsley said, “it turns out that armor plate patterns in the fish are controlled by the same gene that creates this clinical disease in humans. And this finding is related to the old argument whether Nature can use the same genes and create other traits in other animals.”

Ordinarily, “you wouldn't look at that gene and say it's an obvious candidate for dramatically changing skeletal structures in wild animals that end up completely viable and healthy,' he said. "Eda gene mutations cause a disease in humans, but not in the fish. So this is the first time mutations have been found in this gene that are not associated with a clinical syndrome. Instead, they cause evolution of a new phenotype in natural populations.”

The research with the wild fish also shows that the same gene is used whenever the low armor trait evolves. “We used sequencing studies to compare the molecular basis of this trait across the northern hemisphere,” said Kingsley. “It doesn't matter where we look, on the Pacific coast, the East coast, in Iceland, everywhere. When these fish evolve this low-armored state they are using the same genetic mechanism. It's happening over and over again. It makes them more fit in all these different locations.”

Because this trait evolves so rapidly after ocean fish colonize new environments, he added, “we wondered whether the genetic variant (the mutant gene) that controls this trait might still exist in the ocean fish. So we collected large numbers of ocean fish with complete armor, and we found a very low level of this genetic variant in the marine population.”

So, he said, “the marine fish actually carry the genes for this alternative state, but at such a low level it is never seen;” all the ocean fish remain well-armored. “But they do have this silent gene that allows this alternative form to emerge if the fish colonize a new freshwater location.”

Also, comparing what happens to the ectodysplasin signaling molecule when its gene is mutated in humans, and in fish, shows a major difference. The human protein suffers "a huge amount of molecular lesions, including deletions, mutations, many types of lesions that would inactivate the protein," Kingsley said.

But in contrast, “in the fish we don't see any mutations that would clearly destroy the protein.” There are some very minor changes in many populations, but these changes do not affect key parts of the molecule. In addition, one population in Japan used the same gene to evolve low armor, but has no changes at all in the protein coding region. Instead, Kingsley said, “the mutations that we have found are, we think, in the (gene's) control regions, which turns the gene on and off on cue.” So it seems that evolution of the fish is based on how the Eda gene is used; how, when and where it is activated during embryonic growth.

Also, to be sure they're working with the correct gene, the research team used genetic engineering techniques to insert the armor-controlling gene into fish “that are normally missing their armor plates. And that puts the plates back on the sides of the fish,” Kingsley said.

“So, this is one of the first cases in vertebrates where it's been possible to track down the genetic mechanism that controls a dramatic change in skeletal pattern, a change that occurs naturally in the wild,” he noted.

“And it turns out that the mechanisms are surprisingly simple. Instead of killing the protein (with mutations), you merely adjust the way it is normally regulated. That allows you to make a major change in a particular body region - and produces a new type of body armor without otherwise harming the fish.”


TOPICS: Culture/Society; Miscellaneous; Philosophy
KEYWORDS: crevolist; evolution; genetics; godsgravesglyphs; helixmakemineadouble; massextinction; ordovician; phenryjerkalert; trilobite; trilobites
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To: VadeRetro

Scientists are so arrogant! The only reason they dismiss Velikovsky is because they worship the dogma of naturalism. Has anyone actually observed the formation of Venus?


461 posted on 06/01/2005 8:20:40 PM PDT by Nataku X
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To: Right Wing Professor

So not only are the creationists soulmates with the postmoderndeconstructions and harun yahya; they are the Molly Ivins of the conservative movement. Needless to say, the Moderate Creationists never criticize anyone for plagiarism.


462 posted on 06/01/2005 8:26:47 PM PDT by Doctor Stochastic (Vegetabilisch = chaotisch is der Charakter der Modernen. - Friedrich Schlegel)
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To: darbymcgill
I will dissolve back into my lurker mode

Good move. As I'm sure you noticed, the market for folksy pseudo-ingenues is kinda slack here at the moment. Better luck on your next gig.

463 posted on 06/01/2005 8:34:19 PM PDT by Right Wing Professor
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To: Nataku X

Bougereau left this eyewitness painting.

Note: The two-dimensional work of art depicted in this image is in the public domain in the United States and in those countries with a copyright term of life of the author plus 100 years. This photograph of the work is also in the public domain in the United States (see Bridgeman Art Library v. Corel Corp.).

464 posted on 06/01/2005 8:36:19 PM PDT by Doctor Stochastic (Vegetabilisch = chaotisch is der Charakter der Modernen. - Friedrich Schlegel)
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To: Dan Evans

I don't think it is necessarily true that there is "information" in the genome. For example this fractal image was created with nothing but the formula:
Z' = Z^2 + C

There was really no other information. No artist drew it and it wasn't a product of evolution. Yet it appears to have patterns and appears to be a product of intelligent design. <<

It is a design made up from HUMAN mathematical constructs. It appears to be the product of intelligent design...because it is.

Analogies are not proof. Data from "stuff" is. Make a measurement, a reading, or whatever. After you have your data, make a hypothesis. Then find a way to test your hypothesis with new information. Form a theory. Let others refute it. If it is useful, others will use it. If not, everyone sends it to the scrap heap.

That is not what NS is doing now.

DK


465 posted on 06/01/2005 8:45:24 PM PDT by Dark Knight
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To: PatrickHenry
500 or so posts. Sigh.

OK, boys and girls, another in the popular Creation Science/Intelligent Design series that they didn't want you to see--because there's just as much evidence for this as for their version.


Tsimshian Creation Story

At the beginning of the world it was covered in darkness. A chief, a chieftianess and son lived at Kungalas. Although the child was greatly loved, he died without cause. The whole tribe mourned each day beside the boy's lifeless body. One morning instead of her dead son the chieftainess witnessed the rising of a boy out of her son's body which burned brightly. She was overjoyed to see her son come back to life. This glowing boy grew large until his father began to call him a giant. Giant boy ate most of the tribe's food, so his father sent him over the sea to find more to eat. Giant boy flew inland and took with him a stone, a raven blanket and a dried bladder full of berries. He dropped the stone in the ocean and rested upon it. Each time he dropped a stone and rested he created a new rocky island. Giant Boy scattered the berries across the land and created a forest filled with fruit. He scattered the salmon roe and trout roe into the rivers to create an abundance of fish. From this day Giant Boy never lacked food in the new world.


466 posted on 06/01/2005 8:51:55 PM PDT by Coyoteman
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To: Right Wing Professor

I will dissolve back into my lurker mode<
Good move. As I'm sure you noticed, the market for folksy pseudo-ingenues is kinda slack here at the moment. Better luck on your next gig.<<

Ahh the good Professor expresses happiness on shutting down debate, and discourse from someone seeking knowledge.

That fits in with education...how?

Scientific model and testing beliefs...how?

Or are you just one of those educational dinosaurs everyone is waiting to die, so science can advance?

How many times has that idea been expressed in science?

DK

Professor, you really need to work at those social skills, doncha think?


467 posted on 06/01/2005 8:54:13 PM PDT by Dark Knight
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To: Dark Knight
It is a design made up from HUMAN mathematical constructs. It appears to be the product of intelligent design...because it is.

Mathematicians don't design things they discover things just as a physicist discovered the formula

F = G m1 m2 / r^2

for the force of gravity. He didn't construct it. He discovered that nature obeys that law. Likewise with other pure mathematical concepts. No mathematician invented pi or e. They were always there and they will always be there.

What that fractal image proves is that very complex patterns can be created from very simple rules that have no information input. Likewise, physicists have discovered that the universe obeys some very simple rules, perhaps only one rule.

468 posted on 06/01/2005 9:05:07 PM PDT by Dan Evans
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To: UnbelievingScumOnTheOtherSide

Everything has a direct ancestor. You almost certainly do, for instance.


469 posted on 06/01/2005 9:11:32 PM PDT by orionblamblam ("You're the poster boy for what ID would turn out if it were taught in our schools." VadeRetro)
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To: Dark Knight
Analogies are not proof.

Analogies are used all the time in science to build conceptual models that help us understand phenomenon. This is nothing new. It is one of the the ways scientists have worked for centuries.

According to Occam's Razor, the simplest model that best explains the phenomenon is the closest to the truth.

470 posted on 06/01/2005 9:15:18 PM PDT by Dan Evans
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To: Dark Knight
Ahh the good Professor expresses happiness on shutting down debate, and discourse from someone seeking knowledge.

Cue violins.

Professor, you really need to work at those social skills, doncha think?

Spotting sanctimonious phonies is a social skill.

471 posted on 06/01/2005 9:18:20 PM PDT by Right Wing Professor
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To: Dan Evans

Humans make the model. It is descriptive of the phenomena hopefully, but a model is not the phenomena.

Did nature invent E or pi, or are they constructions of humans trying to understand E or pi?

Your understanding of these "rules" are bass ackwards. The rules we use are adequate until a better more descriptive rule comes into use. Occams razor comes into play here.

Our mathematics and reasoning are only descriptive of the phenomena we observe. E and pi are our ways of understanding what natural phenomena are. Not the other way around.

Nature does not bend to our boundries.

In your examples, do they hold true in all examples...near light speed, near a great gravitational forces, or at extremely small distances? No? Does it make a difference if it is a point source or a plane?
You pose that the universe may obey only one rule.

Say it outloud, and you will get the Nobel Prize and the accolades of so many countries your life will be lauded.

But I won't hold my breath.

Fractals are a human construct. One made to mimic nature.

Your proof by analogy is silly.

Your knowledge about physicists is just as silly.

Have fun in this silly thread.

DK


472 posted on 06/01/2005 9:26:54 PM PDT by Dark Knight
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To: Right Wing Professor

Spotting sanctimonious phonies is a social skill.<<

Gee professor, shutting down discourse is a really important skill:

If you have tenure.

If you lack facts.

If you depend on authority (as a logical fallicy)?

If you depend on Ad Hominem attacks to defend your position?

Have fun RWP!

I find you amusing. Unlike that poor soul that actually wanted to learn something from this thread, I take you for your face value. On a forum, you are worth nothing. Your additions to this forums have been:

Nothing.

Learn some social skills RWP, you may find that you will not have to depend on your position to actually convince people.

Ohh, the violins are playing, at the funeral of RWP's arguments. How sad?

DK


473 posted on 06/01/2005 9:38:39 PM PDT by Dark Knight
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To: Dark Knight
Your additions to this forums have been: Nothing.

Actually, I do believe I've posted a substantial body of substantive material. See post 398, or 329, or 310, or 273; I fully appreciate that because you were either unwilling or unable to understand any of it you're inclined to deny it exists, but that's par for the course for a creationist. On the other hand all I've seen from you are sanctimonious platitudes. Do you have anything else to offer, or should I put you on permanent ignore?

474 posted on 06/01/2005 10:09:40 PM PDT by Right Wing Professor
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To: Right Wing Professor

Only my belief that you surely enjoy shutting down belief before convincing anyone.
To: Right Wing Professor
>>well now that you know what I was trying to say, will you reply with full context answer? or will you belittle my grammatical skills for lack of an scientific example?
329 posted on 06/01/2005 11:17:26 AM PDT by flevit >>

When you produce a sticklefish that develops legs and walks on land, or starts breathing air, let me know
Here's a fish that walks on land and breathes air.

I take it that since your challenge has been met, you will concede you lost the argument.

That was a Sticklefish?<<

310 posted on 06/01/2005 10:05:32 AM PDT by Right Wing Professor

Crap logic prof, did you get your stuff off a box of corn flakes?
To: blueblazes
I am referring to the process by which primeval ooze produced amoebas that somehow became shrimp that somehow became fish, that somehow became frogs, that somehow became reptiles that somehow became mammals, that somehow became primates, that somehow became man.
First of all, you should get your basic facts straight. Evolution does not put shrimp on the human ancestral line

More importantly, though, science does not deal in proof, it deals in evidence.

The molecular phylogeny of living things is strong evidence of common ancestry and of evolution by mutation and natural selection. It allows us to construct evolutionary trees for all of life that agree with the fossil evidence, have the mathematical structure predicted by evolutionary theory, and cannot plausibly be explained by alternative theories.


273 posted on 06/01/2005 7:50:33 AM PDT by Right Wing Professor

Again crap logic. You too make many assumptions. Prove them or let your theory die an untimely death.

No one is asking you to prove them but that is your burden.

You're not a scientist in this case.

Oh, sorry, you have CREDENTIALS.

You're silly! You're a hoot.

DK



475 posted on 06/01/2005 10:36:00 PM PDT by Dark Knight
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To: Dark Knight
Again crap logic. You too make many assumptions. Prove them or let your theory die an untimely death.

This is your idea of debate?

Bye.

476 posted on 06/01/2005 10:45:26 PM PDT by Right Wing Professor
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To: Right Wing Professor

No, it is your kind of debate.

Science and you lost kin a long time ago.

You cited a bunch of crappy logic to prove your case.

How unimpressive.

Are you impressed Darby McGill?

What a voice of reason! RWR.

I'm sure 18 year olds (under your authority) are really eager to cite your elegance. Your have to do better and smarter on FR.

DK


477 posted on 06/01/2005 11:08:41 PM PDT by Dark Knight
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To: Dark Knight
I don't mean to be rude DK, and I'm not leaving you hanging out to dry, but I've said all I care to say on this thread.

I feel so utterly dirty and icky like when you accidentally run over a squirrel scampering across the road. It will take me days to wash off the slim I've accumulated by reading the pure evil spewed by the all knowing, unrepentive, never admitted a mistake in their lives, brow beaters of academia.

I will sit with my college bound children, be renewed by there zest for life, their brilliance and their humor. I will encourage them not be be discouraged by the morons and ideologues posing as professors and learn not because of their teachings, but in spite of them
478 posted on 06/01/2005 11:52:20 PM PDT by darbymcgill
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To: Right Wing Professor
You're being trolled.
479 posted on 06/02/2005 3:44:36 AM PDT by PatrickHenry (Felix, qui potuit rerum cognoscere causas. The List-O-Links is at my homepage.)
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To: PatrickHenry

What was your first clue? :-)


480 posted on 06/02/2005 5:29:24 AM PDT by Right Wing Professor
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