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dinosaur DNA revisited
(from a short discussion in Alt.Dinosaurs)
>I do not believe that using dinosaur DNA specimens is as simple as it
>sounds. The DNA has been laying in the ground for more than 65 millions
>years and is fragmentary at best.
Actually, having attended this years Society of Vertebrate Paleontology
meeting in Seattle, and having sat in on the presentation made by Mary
Schwietzer.................... (it read Schweitzer, M. H.: Cano, R. J.;
Starkey, J. R.; Horner, J. R. Multiple lines of evidence for the preservation
of collagen and other biomolecules in undemineralized bone from Tyrannosaurus
Rex............. in the short schedule available to attendees) I heard
enough about this to say it is strongly likely that they've actually
identified material that leaves enough squiggles in the DNA-identifying
protein markers used to test these things. They used 2 seperate methods of
DNA-testing and compared the results to a crocodile and an ostrich. The
squiggles (near protein-markers) were more noticable near were the ostrich
had squiggles, than where the crocodile had squiggles, but they were worried
about contamination from the modern stuff during the tests corrupting the
findings from the T Rex, so they also repeated the 2 tests offsite, without
the bird or crocodile present, and got very similar readings.
By no means can they read this DNA. They have fossil remains of the
DNA, but the DNA is sadly decayed beyond SOME of the protein markers leaving
wiggly lines on the tests sometimes.
There was an abstract also published, but I did not get a copy as these
were only sent to members of the SVP, and not just conference attendees. I
spoke with Jack Horner later, after the paper was presented, and he says
Nature magazine will publish this very shortly.
I would be very much interested in the findings of the new
Tugriken-Shire/Mongolian stuff that were so incredibly well-preserved (the
bones were still white and shiny, and looked like modern bone. Everybody in
the seminar gasped as the photos were shown for the first time. You know the
Velociraptor and Protoceratops locked in combat found in Mongolia? The
preservation of that was horrid compared to these. Splintered bone doesn't
count to me as a detriment to reassembling these, since all the pieces are
preserved and can be placed back together, as opposed to being eroded away)
and the matrix was loose red sandstone that can be blown of with an airjet,
and extremely subtle bones were recovered (such as the possible eardrum of
Veloceraptor and an unhatched-but-only-hours-from-hatching therapod found
still in the egg). This dig was by a Japanese-Canadian team, and the lead
Japanese paleontologist Dr Watabi says they will test for DNA remnants in
these finds. They are Late Cretaceous.
Already I feel these will reveal more about prehistoric DNA due to the
unusual and unique cause of preservation of fossils in Mongolia. In almost
all other fossil finds in the whole world, fossilization was caused by the
body of the animal being preserved in water-sediments, and decaying in place,
OR by covering of volcanic activity (ash or lava flow-and the probable
chemical damage of tissues in the process) BUT Mongolian fossils are
primarily created by sand almost instantly covering the body, quite
frequently the sand is the CAUSE of death. There is no other chemical
reaction in the tissues than dehydration and ossification. This is different
than the other types of fossilization which have the water eroding the
tissue, organics eating the tissue, or chemical reactions by acids or heat in
the tissues, in addition to ossification.
I don't know much more about this; I'm an illustrator, not a biochemist,
but I thought I'd mention it here to see what people had to say.