Spectroscopic analysis supports dinosaur-bird link

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Tyrannosaurus rex: The Denver Museum of Nature and Science's T-rex doing the Funky Chicken, a dance that's been passed down to his barnyard descendents. Photo courtesy Mark Ryan.
Tyrannosaurus rex: The Denver Museum of Nature and Science's T-rex doing the Funky Chicken, a dance that's been passed down to his barnyard descendents. Photo courtesy Mark Ryan.
Researchers have concluded that the collagen protein extracted from the bones of a 68-million year old Tyrannosaurus rex is very similar to that found in a present day chicken. The analysis supports the theory that birds are the closest living descendents of the ferocious prehistoric predators.

Two years ago paleontologist Mary Schweitzer and colleagues at North Carolina State University announced they had discovered soft tissue inside the femur of a Tyrannosaurus that had to be broken in pieces for transport. The vessels and cells discovered inside the bone were so elastic they could still be stretched like rubber bands. Initial studies of the material revealed it to be surprisingly similar to that found in an ostrich. Read Gene’s posting of the story here, and you can examine some of the photos that Bryan posted here.

But now more detailed spectroscopic analysis of the collagen’s amino acids show that they match sequences found in the genomes of modern species. John M. Asara, of the Beth Israel Deaconness Medical Center in Boston did the spectroscopic analysis using amino acid sequences from seven short fragments of collagen. One sequence matched that of a frog, one matched a newt, but three of the sequences matched those of a chicken. Until now skeletal similarities had been mainly used to link to the two species.

“This allows you to get the chance to say, ‘Wait, they really are related because their sequences are related,’” Asara said. “We didn’t get enough sequences to definitely say that, but what sequences we did get support that idea.”

The new results appear this week in the journal Science.

Source story in Minneapolis Star Tribune
National Geographic story on T-rex soft tissue discovery
Science News story on T-rex soft tissue discovery
Wired story on T-rex soft tissue discovery

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Your Comments, Thoughts, Questions, Ideas

A little more info... says:

"Of all the organisms in the sequence database, the one that matched T. rex the closest was the chicken. Now, before assuming that this would be strong evidence that birds are related to dinosaurs, it must be put into perspective. The sequence similarity between the T. rex and the chicken was 58%, while it was only 51% similar to both frogs and newts. This compares with a reported 81% similarity between humans and frogs, and 97% between humans and cows.7 Moreover, while some of the peptide fragments showed sequence matches to chickens, others matched frog, or newt, or even fish and mice. The authors did point out that not all organisms are in the database. Although the chicken was the closest match from the database, it is possible that animals not included could be a closer match. Regardless, such similarity does not prove that the organisms shared an evolutionary ancestor"

"Since these dinosaurs are supposed to have been extinct for at least 65 million years, finding soft tissue was quite a surprise for evolutionists. The soft tissue was only partially mineralized; after the minerals were removed, the tissue was “stretchy” and had the appearance of blood vessels.
The finding of unfossilized dinosaur tissue is a serious blow to the idea of an earth millions of years old, but it is not the only example. Recently, scientists have also obtained DNA from fossil frogs and salamanders that were supposed to be 10 million years old.4
Conventional wisdom held that proteins and DNA could not survive for millions of years. Indeed, an upper limit to the preservation of a stable protein such as collagen was presumed to be about 2.7 million years at 0°C, 180,000 years at 10°C, and only 15,000 years at 20°C.5 Thus, there was much skepticism that what Schweitzer found was really dinosaur soft tissue when it was initially reported. Secular scientists were hesitant to believe that such tissue and proteins could persist for more than 65 million years."

posted on Sat, 04/14/2007 - 10:16am
<em>Liza</em>'s picture
Liza says:

Hey, Science Buzz is an open community, and we welcome participation and perspectives from all comers. However, if you're not submitting original observations, please cite your sources.

The above post is excerpted (in different order than the original) from an article titled Tyrannosaurus rex: a big chicken?", authored by Dr. David A. DeWitt (Director of the Center for Creation Studies and a professor of biology at Liberty University), on a website called "Answers in Genesis: Upholding the Authority of the Bible from the Very First Verse."

Now, there are certainly plenty of people who find 68-million-year-old soft tissue tough to explain, and you're free to post your thoughts about that.

However, I want to remind all readers that Science Buzz is a website of the Science Museum of Minnesota, and we're here to discuss science. Please read our statement on evolution if you're not sure what that means.

posted on Mon, 04/16/2007 - 10:13am
<em>Joe</em>'s picture
Joe says:

I listened to this story on Science Friday. I'll add this to the mix as the story is interesting and there are some great live radio moments.

posted on Fri, 04/20/2007 - 10:56pm
<em>mdr</em>'s picture
mdr says:

Thanks for posting the Science Friday audio clip, Joe. That was good.

posted on Sun, 04/22/2007 - 11:43am
Casey says:

This is soooo awesome I love how you guys can really get the inside scoop!!!!!!

posted on Sun, 04/22/2007 - 1:20pm
Anonymous says:

hey everyone, just thought that i should say that this site is really interesting, i never understood how spectroscopic analysis worked but now i understand that dinosaurs were the most intelligant creature in the world. im so committed to them that i want to transform my body characteristics to morph into a raptor. thankyou for listening...

:)

posted on Sun, 04/22/2007 - 11:39pm

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