Dino blood

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Originally posted by Quetzal:
In what context were the creationists attempting to use this information? The only time I heard the creationists use this argument, it was an attempt to push a "young earth". I.e., since hemoglobin breaks down fairly quickly, dino "hemoglobin" is evidence that they didn't live very long ago, or some such nonsense.

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That is correct, the creationists were saying that the incomplete fossilization and the presence of "red blood cells" were evidence that the T. rex died only a short (ie thousands) of years ago. The paper which presented the real evidence was by Horners group in PNAS, 1997 vol 94 pp6291-6296. The bone had "capped" which means that the ends had fossilized and trapped moisture inside of the bone preventing the interior from fossilizing. This also allowed for the association of the proteins with the bone minerals in a manner very similar to protein purification and stabilization on hydroxyapatite, a calcium phosphate matrix used in biochemeistry that has a number of similarities to the general mineral composition of bone. The apatite matrix within the bone helps to protect protein from long term hydrolytic damage. The "red blood cells" found within the bone were actually "ghosts" comprised of completely oxidized heme breakdown products and polypeptide strands. The sample was so old that the amino acids within the polypeptide strands had undergone racimization, ie they were comprised of a mixture of L and D amino acids. There is no way that this sample was only a few thousand years old.This was actually a very cool find as the polypeptide strands obtained were sufficient to demonstrate that the T. rex was relatively close in relationship to a chicken based on immunology of the remaining hemoglobin polypeptide strands within the bone. For the parents in the audience than means that Elmo was really being chased by a T. rex and not a giant chicken .------------------
"Chance favors the prepared mind." L. Pasteur
TazEdited by Adminnemooseus, : Fix quote box.

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Originally posted by Quetzal:
Sorry about that TC. Just another example why it's difficult to take YECs seriously - no offense and present company excepted. NONE of the main YEC organizations have any credibility whatsoever because they are ALWAYS coming up with this kind of (deliberate?) misunderstanding of actual science.

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OTOH, it's probably pretty good tactics if you're just trying to impress people without much of a science background. After all, how many people do you know that could read and/or understand the PNAS article I referenced - Horner's original, as Dr. T pointed out - enough to pick up on what was really found? Let alone the importance of the discovery for everything from cladistics and paleontology to protein evolution?

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Actually Duane Gish should know about the difference between "red blood cells" and what was actually found by Horners group; Gish's training was (it depresses me to admit) in biochemistry. The only way that garbage such as the statement that the dino bone meant a young earth could be mentioned on the ICR and certian related websites would be a depressing ability, desire and willingness to lie concerning the data .------------------
"Chance favors the prepared mind." L. Pasteur
Taz

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Originally posted by Andor:
I think racimization is used as a helping tool in geochronology. I have been searching and though I've actually found a number of references, none give numerical data. Could it be an uncontroversial, independent of radiodating, prove against YEC?

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I have read a few thing concerning rates of racinization but that was a LONG time ago. From what I do remember there are two large problems with its use for dating: the first is the variability inherent within the racimization rates due to conditions, as well as a lack of internal control that is found with the most advanced radioactive dating techniques which actually use single crystals; the second is that, while not unknown, the presence of organics in sufficient quantity or of sufficient quality to do the dating is very, very rare. Most of the ones that I am familiar with are based on some sort of bone or bone associated protein and would probably not be enough for a wide spread technique. I need to look up the most recent research in this area in my copious spare time .------------------
"Chance favors the prepared mind." L. Pasteur
Taz

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[This message has been edited by Dr_Tazimus_maximus, 06-11-2002]

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Originally posted by Quetzal:
So's Behe - wonder what it is about biochemists? (Sorry Dr. T, couldn't resist.)

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Actually I think that Behe is more a molecular biologist. If you want something really amusing, look at the extremely high number of engineers in the ICR and related groups. Something in their training makes them look for design I guess .------------------
"Chance favors the prepared mind." L. Pasteur
TazEdited by Adminnemooseus, : Fix quote box.

One last comment on fossil proteins before I go back to lab. There are a number of papers that groups such as the ICR use, ie misrepresent, for their young earth arguements. If anyone hears one concerning a bone protein called osteocalcin (Geology 1992 v20 pp871-874) it again does nothing to prove a young earth. It is another complexed bone protein and it is detected almost solely by the presence of a single modified amino acid (gamma-carboxy glutamate) and not the presence of an intact protein as indicated by some YEC's.------------------
"Chance favors the prepared mind." L. Pasteur
Taz