Chicken with teeth - take that creationist

Azazal · Post by **Azazal** » 2006-02-24 11:27am

Susanne Rust
Milwaukee Journal Sentinel
Feb. 23, 2006 10:55 AM

MILWAUKEE - Matthew Harris didn't flinch at the crocodilian-like teeth flashing six inches in front of his face. He didn't scream or whimper, either.

Instead, he sat back, shook his head and leaned in for a better look.

That's because Harris, a researcher at the University of Wisconsin-Madison last year, wasn't looking into the mouth of a giant, dentition-ridden reptile.

He was looking into the mouth of a chicken.

Harris, who is now at a research institute in Germany, and a team of researchers from the University of Wisconsin-Madison and the University of Manchester in England have discovered teeth in a mutant line of chickens.

And their discovery supports the premise that ancient genetic signals can be resurrected - remaining dormant or not expressed in an organism's DNA - for millions of years, waiting for the right conditions to spark their return.

This is a phenomenon known to developmental biologists and geneticists as atavism, popularly called "throwbacks."

The discovery also sheds light on the molecular and developmental mechanisms behind tooth loss and beak growth in birds, giving paleontologists a bird's-eye view of the biological processes that took place millions of years ago, as one line of a raptor-like dinosaur crossed the taxonomic boundary from reptile to bird.

The paper appears in this week's issue of Current Biology.

"I find the paper to be an impressive demonstration of the molecular basis of an atavism," said Richard Prum, an evolutionary biologist at Yale University who was not involved in the study.

Tooth growth in birds has been discussed, debated and ridiculed for nearly 200 years. In 1882, noted French biologist Geoffroy St. Hilaire claimed to have seen something that looked like rudimentary reptilian teeth on the jaw of a parrot - teeth that later disappeared when the beak grew.

Excited and perplexed, he discussed his publication with Georges Cuvier, a well-known French anatomist. He told Cuvier the teeth resembled those of reptiles.

Cuvier dismissed his findings and told St. Hilaire he was mistaken. The subject fell silent, despite a couple of peeps by other scientists who had observed "hen's teeth" later that century.

Then, in the 1970s, researchers discovered that if they introduced mouse oral tissue into the mouth of a developing chick, the chicken could be coaxed to grow teeth. Apparently, the molecular signaling in mouse tissue spurs the chicken to respond with tooth-bearing instructions.

The discovery provoked further investigations into chicken teeth and a revitalized interest in the concept of atavism - sparking scientists to look into the role of embryonic development as a way of understanding the evolution of birds.

But the chickens in these experiments didn't grow just any old teeth. They grew teeth that looked like molars. And this had some scientists scratching their heads.

If, indeed, the teeth they were seeing in these birds were "throwbacks" to their dinosaur-like ancestors, then why were they growing mammal teeth instead of reptile teeth?

It is believed that birds descended from raptor-like dinosaurs around 70 million to 80 million years ago. (The link between mammals and birds goes back 300 million years.)

So, given that chicken jaws could be prompted to develop teeth - even if they were the wrong kind - researchers wondered, was it possible the signal still resided in living birds? And if it did, what could it tell them about the evolutionary history of tooth loss in birds?

Harris, who is now at the Max Planck Institute in Germany, and John Fallon, an anatomist at the University of Wisconsin, seem to have stumbled on the answers, although that wasn't their initial intention.

Harris and Fallon had been looking at a particular strain of mutant chickens to see what they could uncover about the development of feathers and scales. The chickens have several developmental abnormalities and do not generally survive to hatch.

It was while Harris was looking at these chickens that he made his startling discovery. Even though he and other researchers had looked at the embryos hundreds if not thousands of times, no one had noticed the little tooth buds growing in the jaws.

"It was like finding gold in the bathroom," said Harris.

Harris showed Fallon, and the two consulted Mark Ferguson, an expert on alligator teeth at the University of Manchester. He agreed that they looked like first-stage, or "baby," teeth in alligators, the closest living relatives to birds. And they appeared to develop in a similar fashion.

The observation vindicates St. Hilaire's publication.

The question then became: Why is this happening in this mutant strain?

The authors propose that these chickens express a genetic mutation code that brings together two layers of the chicken's embryonic mouth, which are separated in normal chickens.

"It's like having two handset radios that don't work," said Fallon. "With a little tweaking and adjusting, you can get them to work again" to receive and transmit signals to one another.

In an additional test, the researchers found that teeth formation can be initiated in normal chickens, too, with the right molecular rejiggering.

Julia Clarke, a paleontologist at North Carolina State University who specializes in raptor-like dinosaurs, said the findings will shed light on the dinosaur fossil record, indicating potential mechanisms for different patterns of tooth loss observed in various lines of dinosaurs.

"Some have no teeth present in the beak tip," while others have none in the back of the mouth, she said. This work provides a mechanism by which such variations can be explained.

It also points to the "incredible conservation of genetic mechanisms" that control not only tooth formation, but other characteristics as well.

"I wonder what is the longest instance of a character being retained" throughout evolution, Clarke asked. Tens of millions of years? Hundreds of millions of years?

"This is exactly what we'd predict"-the genetic linking of a living animal and its ancestors-by using an evolutionary approach to biology, she said.

Wicked Pilot · Post by **Wicked Pilot** » 2006-02-24 11:35am

It's just Satan trying to trick us.

Flakin · Post by **Flakin** » 2006-02-24 11:47am

Wicked Pilot wrote:It's just Satan trying to trick us.

Nonononono. It's a test of your faith from God.

This is pretty fascinating though. Some pictures would be interesting.

CaptainChewbacca · Post by **CaptainChewbacca** » 2006-02-24 11:50am

Ok, chickens with teeth is about a "7" on my weird-shit-o-meter.

Darth Servo · Post by **Darth Servo** » 2006-02-24 11:59am

I guess the TNG episode "Genesis" isn't quite so far-fetched afterall

Wicked Pilot · Post by **Wicked Pilot** » 2006-02-24 12:03pm

Flakin wrote:Nonononono. It's a test of your faith from God.

They're both conspiring against us. Have you ever read the book of Job?

Post by **LadyTevar** » 2006-02-24 12:32pm

... Damn... hen's teeth aren't that rare after all.

Molyneux · Post by **Molyneux** » 2006-02-24 04:00pm

LadyTevar wrote:... Damn... hen's teeth aren't that rare after all.

Well, considering that it requires genetic tinkering in order to get a chicken with teeth to survive past the egg stage, I wouldn't say they're common as all that...

Gil Hamilton · Post by **Gil Hamilton** » 2006-02-24 04:13pm

CaptainChewbacca wrote:Ok, chickens with teeth is about a "7" on my weird-shit-o-meter.

9 out of 13 on the weird-shit-o-meter for me. These chickens are turn back into their evolutionary great great granddaddies, the velociraptor!

Utsanomiko · Post by **Utsanomiko** » 2006-02-24 04:19pm

He should pull that chicken's teeth out and sell them on eBay.

But Creationists will have an excuse like always. I wouldn't mind hearing a few of their cracks at it, but they'll settle on an official responce eventually.

Post by **LadyTevar** » 2006-02-24 04:47pm

I mentioned this to the office YEC, and he brought up the fossil with human and dinosaur prints side by side.

I laughed at him and told him that thing was proven a fake 20yrs ago, and asked who'd been telling him that lie recently. He walked off without answering.

Azazal · Post by **Azazal** » 2006-02-24 04:51pm

Gil Hamilton wrote:
CaptainChewbacca wrote:Ok, chickens with teeth is about a "7" on my weird-shit-o-meter.
9 out of 13 on the weird-shit-o-meter for me. These chickens are turn back into their evolutionary great great granddaddies, the velociraptor!

Nahh, go for the gosto, T-rex. It would be interesting if they could combine this new discovery with the soft tissue they found last year and through the "magic" of science, give birth to something

wautd · Post by **wautd** » 2006-02-24 05:51pm

Chicken is already one of the most lethal foods. Now they are getting fucking teeth as well? Thank the Allmighty they are still stupid or we were boned

Admiral Valdemar · Post by **Admiral Valdemar** » 2006-02-24 06:14pm

If Avian Flu doesn't get you, rabid chickens with teeth will maim you like the little Link you are.

DPDarkPrimus · Post by **DPDarkPrimus** » 2006-02-24 08:02pm

"It's just a mutation, it proves nothing!"

TheBlackCat · Post by **TheBlackCat** » 2006-02-24 08:42pm

Admiral Valdemar wrote:If Avian Flu doesn't get you, rabid chickens with teeth will maim you like the little Link you are.

Indeed, Ganon would be a walk in the park compared to an army of deranged, fanged cuckoos.

Majin Gojira · Post by **Majin Gojira** » 2006-02-24 09:04pm

Aww...I was hoping for pics. Now I'll have to pick up that journal and hope there aer some there...

Pick · Post by **Pick** » 2006-02-24 11:01pm

Finally I can get my evil Satanistic summoning supplies.

Now hurry up, I need some frog fur.

Wyrm · Post by **Wyrm** » 2006-02-25 12:37am

DPDarkPrimus wrote:"It's just a mutation, it proves nothing!"

FREDDY THE FUNDIE SEZ: "HALELUJA, BROTHER! Don't believe the lies of the evil Ay-theists! The EVIL AY-THEIST CONSPIRACY will be demolished soon, and the BIBLE will be vindicay-ted as the truth of the LAWRD!"

Hey, Freddy, it's been a while...

FREDDY: "HA! You'll NEVER git ridda ME, you dirty evil-lution-believin' sinnah! The BIRD TEETH are just a mu-taaaaay-tion of the LAWRD'S great design! THE INTELLIGENT DESIGN WILL TRIUMPH OVAH YER PUNY RANDOM THEERAH!"

Look, if a simple mutation can produce an entire complicated system like teeth, how can you say that such systems are too complicated to evolve?

FREDDY: "Um... er..."

Or, if the chicken had the capability to grow teeth all along, why did God choose to include the genetic machinery to grow teeth, only to switch the entire system off in all birds.

FREDDY: "Ah... Er... D-D-DON'T TRY TO CONFUSE ME, SINNAH!! My lawrd JEEEEEZIS, purge this SINNAH of evil-lution and become a weapon of the LAWRD against the ay-theists! WAKE HIM UP TO THE LUV A' TH' LAWRD, JEEEEEEEEEEZIIIII--"

*WHANG!*

FREDDY: "oooh, lookit all da crucifixes!"

Post by **The Yosemite Bear** » 2006-02-25 04:05pm

LadyTevar wrote:... Damn... hen's teeth aren't that rare after all.

quick to the potions chamber!

Darth Raptor · Post by **Darth Raptor** » 2006-02-25 08:40pm

DPDarkPrimus wrote:"It's just a mutation, it proves nothing!"

Actually, it proves a common Designer.

Molyneux · Post by **Molyneux** » 2006-02-27 08:53am

Darth Raptor wrote:
DPDarkPrimus wrote:"It's just a mutation, it proves nothing!"
Actually, it proves a common Designer.

...albeit one with way too much time on Hir hands, with a flair for half-assery and jury-rigged solutions.

TheBlackCat · Post by **TheBlackCat** » 2006-02-28 12:02pm

Darth Raptor wrote:Actually, it proves a common Designer.

You are correct, assuming the designer you are talking about is evolution.

drachefly · Post by **drachefly** » 2006-02-28 03:03pm

Junk DNA had to be for something... now we know what it's there for. It's the back room full of useful-looking stuff you don't need right now.. like teeth.

TheBlackCat wrote:
Admiral Valdemar wrote:If Avian Flu doesn't get you, rabid chickens with teeth will maim you like the little Link you are.
Indeed, Ganon would be a walk in the park compared to an army of deranged, fanged cuckoos.

In Link to the Past, it is infinitely easier to kill Ganon than it is to kill a chicken. And yes, there are chickens, and yes, you can attack them.

Post by **Darth Wong** » 2006-02-28 04:00pm

The beauty of Intelligent Design, from the perspective of its proponents, is that the designer need not actually act in an intelligent fashion. That's why you can never disprove intelligent design: the most obvious way to disprove it would be to point out examples of unintelligent design, and IDers dismiss all such examples as our own inability to understand God's grand design.

In other words, they believe that if something seems intelligent, it proves that an intelligent God designed it. And if something seems stupid, it proves that an inscrutable God designed it.