Posted on 04/12/2007 12:43:57 PM PDT by AdmSmith
68-million-year-old T. rex proteins are oldest ever sequenced
Scientists have confirmed the existence of protein in soft tissue recovered from the fossil bones of a 68 million-year-old Tyrannosaurus rex (T. rex) and a half-million-year-old mastodon.
Their results may change the way people think about fossil preservation and present a new method for studying diseases in which identification of proteins is important, such as cancer.
When an animal dies, protein immediately begins to degrade and, in the case of fossils, is slowly replaced by mineral. This substitution process was thought to be complete by 1 million years. Researchers at North Carolina State University (NCSU) and Harvard Medical School now know otherwise.
The researchers' findings appear as companion papers in this week's issue of the journal Science.
"Not only was protein detectably present in these fossils, the preserved material was in good enough condition that it could be identified," said Paul Filmer, program director in the National Science Foundation (NSF) Division of Earth Sciences, which funded the research. "We now know much more about what conditions proteins can survive in. It turns out that some proteins can survive for very long time periods, far longer than anyone predicted."
Mary Schweitzer of NCSU and the North Carolina Museum of Natural Sciences discovered soft tissue in the leg bone of a T. rex and other fossils recovered from the Hell Creek sediment formation in Montana.
After her chemical and molecular analyses of the tissue indicated that original protein fragments might be preserved, she turned to colleagues John Asara and Lewis Cantley of Harvard Medical School, to see if they could confirm her suspicions by finding the amino acid used to make collagen, a fibrous protein found in bone.
Bone is a composite material, consisting of both protein and mineral. In modern bones, when minerals are removed, a collagen matrix--fibrous, resilient material that gives the bones structure and flexibility--is left behind. When Schweitzer demineralized the T. rex bone, she was surprised to find such a matrix, because current theories of fossilization held that no original organic material could survive that long.
"This information will help us learn more about evolutionary relationships, about how preservation happens, and about how molecules degrade over time, which could have important applications in medicine," Schweitzer said.
To see if the material had characteristics indicating the presence of collagen, which is plentiful, durable and has been recovered from other fossil materials, the scientists examined the resulting soft tissue with electron microscopy and atomic force microscopy. They then tested it against various antibodies that are known to react with collagen. Identifying collagen would indicate that it is original to T. rex--that the tissue contains remnants of the molecules produced by the dinosaur.
"This is the breakthrough that says it's possible to get sequences beyond 1 million years," said Cantley. "At 68 million years, it's still possible."
Asara and Cantley successfully sequenced portions of the dinosaur and mastodon proteins, identifying the amino acids and confirming that the material was collagen. When they compared the collagen sequences to a database that contains existing sequences from modern species, they found that the T. rex sequence had similarities to those of chickens, and that the mastodon was more closely related to mammals, including the African elephant.
The protein fragments in the T. rex fossil appear to most closely match amino acid sequences found in collagen of present-day chickens, lending support to the idea that birds and dinosaurs are evolutionarily related.
"Most people believe that birds evolved from dinosaurs, but that's based on the 'architecture' of the bones," Asara said. "This finding allows us the ability to say that they really are related because their sequences are related."
"Scientists had long assumed that the material in fossil bones would not be preserved after millions of years of burial," said Enriqueta Barrera, program director in NSF's Division of Earth Sciences. "This discovery has implications for the study of similarly well-preserved fossil material."
He’s no doubt thinking of DNA sequencing, which this is not.
I recall a rather extended exchange with someone over the phrase “recessive genes” as applied to bacteria. It appears that terminology is not strict enough to avoid misunderstandings, when misunderstanding is the goal.
Son, when you learn some science and have practiced it for a couple of decades, then you can lecture us on it.
You seem to think that you can do a quick scan of AnswersInGenesis and become an expert on science. It doesn't work that way.
You know where you can take your false pedantry.
This isn’t science, it’s pure propaganda, sonny boy.
Your problem is that you don’t understand well enough to realize that you’re defending the ridiculous.
Uhh...Cause our ancestors would have been eaten if they existed at the same time as them.
Cruelly enough, “nipple-teeth” were indeed mammals...
“Mastodons or Mastodonts (meaning ‘nipple-teeth’) are members of the extinct genus Mammut of the order Proboscidea and form the family Mammutidae; they resembled, but were distinct from, the woolly mammoth which belongs to the family Elephantidae... Kingdom: Animalia Phylum: Chordata Class: Mammalia Order: Proboscidea Family: Mammutidae Genus: Mammut”
http://en.wikipedia.org/wiki/Mastodon
“Proboscidea is an order containing only one family of living animals, Elephantidae, the elephants, with three living species (African Bush Elephant, African Forest Elephant, and Asian Elephant)”
http://en.wikipedia.org/wiki/Proboscidea
“The elephants (Elephantidae) are a family of pachyderm, and the only remaining family in the order Proboscidea in the class Mammalia. Elephantidae has three living species: the African Bush Elephant, the African Forest Elephant (until recently known collectively as the African Elephant), and the Asian Elephant (also known as the Indian Elephant). Other species have become extinct since the last ice age, which ended about 10,000 years ago, the Mammoth being the most famous of these. Elephants are mammals...”
http://en.wikipedia.org/wiki/Elephantidae
“The protein fragments in the T. rex fossil appear to most closely match amino acid sequences found in collagen of present-day chickens, lending support to the idea that birds and dinosaurs are evolutionarily related.”
“T. rex Francese.” Has an appetizing ring to it. But the left-overs would defintely be a problem.
First off, Race's comment was beyond the pale and my response has nothing to do with his posts.
This bone has measurable/detectable amounts of C-14 in it. We are told that the C-14 is there from water contamination and not because it was there when the dino was alive. Therefore, if ground water contamination is the source for C-14, the fossils themselves cannot therefore be considered hermetically sealed.
I think he just had the wrong article. They have two, one with antibody affinity studies and the other with the protein sequencing data. He picked up the antibody affinity one and said, “Hah! There’s no sequencing here!”
Trace amounts of C14 can be created by radioactivity in rocks.
Does is come with biscuits?
Oh good grief. Pointing out that a community college junior? sophomore? who’s apparently not even majoring in the sciences can’t claim to be thoroughly educated in them is “elitist”? Truly you are a child of the 80’s self-esteem craze.
By the way, yesterday I found myself reading “bicep” as “biccup”. Thanks.
“Not surprisingly, since the mastodon was a mammal.”
LOL! Exactly what I thought, but reading your comment was funnier.
How does this C-14 get transferred into the fossil? I.e. would the reaction not have to take place in the fossil itself?
Also, are the scientists studying this fossil specifically stating racioactive rocks as the source of C-14?
We can probably expect many studies similar to this one on other samples in a few months. 2007 will be an interesting year.
So far I haven’t seen anyone mention C-14 but you. We’re willing to stipulate that trace amounts of C-14 might be present if searched for. The scientists studying this fossil are unlikely to do that because they know what they’d find—little if any detectable C-14.
Regarding the source of the C-14, it could be produced by radioactive decay in the surrounding rocks. Radiation could be absorbed by a nitrogen atom in the fossil. The energized nitrogen atom could then be converted to C-14 by either positron emission or K electron capture. I’m not sure which would be more energetically favorable in this case, but either one would get the job done. The fossil has plenty of nitrogen in it to work with, and mundane rock can contain levels of radiation high enough to make a pretty alarming series of clicks on a Geiger counter.
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