Researchers Trace Evolution to Relatively Simple Genetic Changes

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.

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.”

"And you COMPLETELY MISS my point while making it for me. Evolutionary biologists have already accepted that evolution is a fact and are just looking for pieces that fit into their puzzle and routinely ignore any that do not yet never once do they stop question the basic premise of evolution. "

Care to back that assertion up with a little more than your opinion? Give an example of them dismissing something that goes against the ToE?

"Here, case in point, in the past in order to "convince" (read that "indoctrinate") people as to the validity of the theory of evolution, they used to use a chart of a horse and some smaller horselike creatures that they claimed were ancestors of the horse in some distant epoch. However, when you carefully examine the skeletons you notice that the creatures gained and lost pairs of ribs at random as it "evolved". As more people began to question this, the evolutionists backed off the validity and eventually the chart used to indoctrinate MILLIONS was discredited as innaccurate."

If you would look at taxonomy, you would see that some are considered in the direct lineage and others are in offshoot lineages. You created a strawman to attack.

"And how many scientist "prove" evolution is to say, well, this extinct critter looks somewhat (or maybe even a lot) like this living critter, so therefore it evolved from this extinct critter."

Have you ever looked at the methods used to determine if a specific extinct organism is related to a specific extant organism? If not, then maybe you should.

"This would be a great example of evolution if (1) evolution was directed toward a specific goal, and (2) evolution didn't require the intermediates to be stable. Since both of these are false, the example is meaningless.

Before we go any further, are we taking a gene or an organism?

"A better example is to start with a sentence, and then see how long it takes to morph into a completely different sentence, with all of the intermedia sentences making sense. Of course, this still leaves the problem of the origin of the first sentence, which is still just as problematic and combinatorially improbable as before.

This also requires the end result be known. Nor does it take into account the intermediate failures that are discarded.

Marshe's horse theory was tossed.

Nebraska man was a pig.

Ramapithecus was a mistake.

Peking Man

Java Man

Lucy

Misplaced fossils: "Evolutionists believe, for example, that the land plants didn't appear until over 100 million years after the Cambrian trilobites died out. Yet over sixty genera of woody plants, spores, pollen, and wood itself have been recovered from lowest 'trilobite rock' (Cambrian) throughout the world. The evidence is so well known that it's even in standard college and biology text books.

The problem with NS as the Theory of Evolution is: The only people questioning it, are IDers! It is a scientific corruption, not real science and devoid of scientific principle.

DK

Did you read your posted evidence?

It started with:
>>The recognition and interpretation of patterns in the fossil record require an awareness of the limitations of that record. Only a very small fraction of the species that have lived during past geologic history is preserved in the rock record.<<

Gads man, do you teach? You should administrate!

>>The horse series was constructed from fossils found in many different parts of the world, and nowhere does this succession occur in one location. The arrangement of the evolution of horse is made by aligning various fossils found in India, South America, North America and Europe, in a series from the smallest to the largest. (Modern horses range from 17" to 80" in size)<<

Cope's Rule was WRONG. And is still taught.

This is from that bastion of Creationism, University of Chicago.

>>Jablonski gave two reasons why Cope's Rule has so thoroughly permeated paleontological thinking, and both of them are psychological. "Believing that larger body size bestowed long-term evolutionary advantages fit our preconceptions that body size is important in the short term. Size determines who you can eat and who eats you, how widely you can range and your mating success. Secondly, there is a human tendency to focus on the largest animals: the biggest horse in a given time slice, for example.<<

http://chronicle.uchicago.edu/970123/jablonski.shtml

>>Cope's Rule that evolutionary lineages have a tendency to evolve toward larger body size is one of the most long-standing evolutionary "laws." E.D. Cope first formulated his now-famous rule in a book published in 1896, and it is cited widely in textbooks from elementary to graduate school.<<

VadeR...it took one hundred years for NS Evolutionists to actually test a cherished RULE. It was wrong. But it took one hundred years before someone did the testing.

The tools to test were not more exotic than scales and micrometers. NS Evolutionists chose not to do it.

NS Evolution is not a real science.

And I have to explain this to a smart guy?

DK

The Teacup poodle is a small toy poodle that measures 9 inches and smaller.

Compared to a Great Dane or a Bullmastiff, WWETU?

What would evolution tell us?

Did you read your posted evidence? It started with:

>>The recognition and interpretation of patterns in the fossil record require an awareness of the limitations of that record. Only a very small fraction of the species that have lived during past geologic history is preserved in the rock record.<<

Gads man, do you teach? You should administrate!

How dumb are you willing to play before you get some sense of shame? The source is saying that there are holes in the fossil record because fossilization conditions are rare. That is, there are holes in the recording process. You are claiming that any holes in the fossil record are actual holes in the history of life. You maintain this position although you refuse to specify what exactly you are talking about. Why should there be unbridgeable holes in the history of life? What O what does a person who is not a creationist say is filling those holes?

There's nothing to do here but point out how transparently dishonest you are. Seriously, there's nothing else to say. Where are the good arguments?

When do you explain the horse series? Stop your silly-assed tap-dancing and ANSWER THE QUESTION. Why is there a horse SERIES?

Here was the question:

Did ~~God~~ Something that wasn't evolution create Hyracotherium, then kill off Hyracotherium and create some Hyracotherium-Orohippus intermediates, then kill off the intermediates and create Orohippus, then kill off Orohippus and create Epihippus, then allow Epihippus to "microevolve" into Duchesnehippus, then kill off Duchesnehippus and create Mesohippus, then create some Mesohippus-Miohippus intermediates, then create Miohippus, then kill off Mesohippus, etc.....each species coincidentally similar to the species that came just before and came just after?
~~Creationism~~Anything-but-evolutionism utterly fails to explain the sequence of known horse fossils from the last 50 million years. That is, without invoking the "~~God~~Something That Wasn't Evolution Created Everything To Look Just Like Evolution Happened" Theory.

What's the problem here? The series is there. It isn't there because of some law. It's there because it's there. Are you really going to pretend you're too stupid to understand? What does that prove, even if you convince someone you're too stupid to understand?

Did you read your posted evidence? It started with:

Gads man, do you teach? You should administrate!

There's nothing to do here but point out how transparently dishonest you are. Seriously, there's nothing else to say. Where are the good arguments?

When do you explain the horse series? Stop your silly-assed tap-dancing and ANSWER THE QUESTION. Why is there a horse SERIES?

Here was the question:

Did ~~God~~ Something that wasn't evolution create Hyracotherium, then kill off Hyracotherium and create some Hyracotherium-Orohippus intermediates, then kill off the intermediates and create Orohippus, then kill off Orohippus and create Epihippus, then allow Epihippus to "microevolve" into Duchesnehippus, then kill off Duchesnehippus and create Mesohippus, then create some Mesohippus-Miohippus intermediates, then create Miohippus, then kill off Mesohippus, etc.....each species coincidentally similar to the species that came just before and came just after?
~~Creationism~~Anything-but-evolutionism utterly fails to explain the sequence of known horse fossils from the last 50 million years. That is, without invoking the "~~God~~Something That Wasn't Evolution Created Everything To Look Just Like Evolution Happened" Theory.

Maybe I would treat your arguments more seriously if you weren't copy-pasting them without citing the source.

Misplaced fossils: "Evolutionists believe, for example, that the land plants didn't appear until over 100 million years after the Cambrian trilobites died out. Yet over sixty genera of woody plants, spores, pollen, and wood itself have been recovered from lowest 'trilobite rock' (Cambrian) throughout the world.

I call bullshit. No such things have been genuinely been found in the lower cambrian.

The problem with NS as the Theory of Evolution is: The only people questioning it, are IDers! It is a scientific corruption, not real science and devoid of scientific principle.

What is NS as the Theory of Evolution? And how exactly are "IDers" questioning it?

Nebraska man was a pig. Ramapithecus was a mistake. Peking Man Java Man Lucy

What are Java Man and Lucy doing in that list? They are part of the thousands of genuine transitional fossils. Its a shame you can only find less than a handful of frauds and mistakes amongst the thousands of genuines. You think Java Man and Lucy are the only fossil evidence for evolution of man? They are not. You probably haven't heard of most of the others because anti-evolution propaganda sites tend to keep quiet about them. Such is the problem with the BS of the "theory" of Intelligent Design.

Could happen to anyone. Early morning stuff.

>>When do you explain the horse series? Stop your silly-assed tap-dancing and ANSWER THE QUESTION. Why is there a horse SERIES?<<

Remember, this series has chains that are separated by continents and millions of years, a tree based on morphology, with many more missing parts than parts. I give you a 500 piece puzzle with ten pieces, and you want to crow about a series based on morphology.

I believe that genetics will settle most of the questions on NS ToE. It will provide actual roots, maybe a mechanism that we will test. The hard sciences...you know.

NS ToE is squishy and soft.

Sound like a creationist to me.

Ooops, you can't even get your head out of your hate mode long enough to realize there is more than one opposing view on this topic.

What a sad, tired, pathetic place to be.

Have a good morning!

DK

Let's get all the "frauds" out of the way. In the 150 year history of this research since Darwin, the tens of thousands of scientists working in this field, and the millions of fossils uncovered, this is it. Maybe I've left out one or two:
Piltdown Man. Science (not creationism) uncovered the fraud.
Nebraska Man. It wasn't much of a fraud.
Peppered Moths. Another non-issue.
Haeckel's Embryos. Yet another.
Archaeopteryx. Despite howls from creationists, it's not a fake.
Archaeoraptor. A crude fake, publicised by Nat'l Geographic, then quickly exposed.
Lucy. The "fraud" claim is actually a creationist fraud.

Now then, contrast that to the frauds and lies on every creationist website.

I'm a Creationist!

God created the Universe approximately
4.5 billion years ago and has been active
in its evolution ever since.

He's is not hasty. He takes his time.
Occasionally He will take a rest. On
other occasions he will work with a
flurry of activity. His work
is wonderful.

It is left to us to divine His hand. The
more His Truths are discovered through the
methodology of Science the more beautiful
His Creation becomes.

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