Newswise – Paleontologists have been stunned by the discovery of softtissue from dinosaurs. The tissue is 68 to 80 million yearsold, and some of it remains pliant. The tissue from aTyrannosaurus Rex tissue is virtually identical to a modernostrich. The tissue probably contains genetic material.Perviously, it had been thought that organic tissue couldnot survive beyond a hundred thousand years.
This means that the world’s very archaic fossils may containa wealth of genetic material that will open a completely newwindow for us onto life in the distant past.
Dr. Mary Schweitzer, assistant professor of paleontologywith a joint appointment at the N.C. Museum of NaturalSciences, has succeeded in isolating soft tissue from thefemur of a 68-million-year-old dinosaur. Not only is thetissue largely intact, it?s still transparent and pliable,and microscopic interior structures resembling blood vesselsand even cells are still present.
In a paper published in the March 25 edition of the journalScience, Schweitzer describes the process by which she andher technician, Jennifer Wittmeyer, isolated soft organictissue from the leg bone of a 68-million-year-oldTyrannosaurus rex.
Schweitzer was interested in studying the microstructure andorganic components of a dinosaur?s bone. All bone is made upof a combination of protein (and other organic molecules)and minerals. In modern bone, removing the minerals leavessupple, soft organic materials that are much easier to workwith in a lab. In contrast, fossilized bone is believed tobe completely mineralized, meaning no organics are present.Attempting to dissolve the minerals from a piece offossilized bone, so the theory goes, would merely dissolvethe entire fossil.
But the team was surprised by what actually happened whenthey removed the minerals from the T. rex femur fragment.The removal process left behind stretchy bone matrixmaterial that, when examined microscopically, seemed to showblood vessels, osteocytes, or bone building cells, and otherrecognizable organic features.
Since current data indicates that living birds are moreclosely related to dinosaurs than any other group,Schweitzer compared the findings from the T. rex withstructures found in modern-day ostriches. In both samples,transparent branching blood vessels were present, and manyof the small microstructures present in the T. rex sampledisplayed the same appearance as the blood and bone cellsfrom the ostrich sample.
Schweitzer then duplicated her findings with at least threeother well-preserved dinosaur specimens, one80-million-year-old hadrosaur and two 65-million-year-oldtyrannosaurs. All of these specimens preserved vessels,cell-like structures, or flexible matrix that resembled bonecollagen from modern specimens.
Current theories about fossil preservation hold that organicmolecules should not preserve beyond 100,000 years.Schweitzer hopes that further research will reveal exactlywhat the soft structures isolated from these bones are madeof. Do they consist of the original cells, and if so, do thecells still contain genetic information? Her early studiesof the material suggest that at least some fragments of thedinosaurs? original molecular material may still be present.
?We may not really know as much about how fossils arepreserved as we think,? says Schweitzer. ?Our preliminaryresearch shows that antibodies that recognize collagen reactto chemical extracts of this fossil bone. If further studiesconfirm this, we may have the potential to learn more notonly about the dinosaurs themselves, but also about how andwhy they were preserved in the first place.?
The research was funded by NC State, the N.C. Museum ofNatural Sciences and the National Science Foundation.
Photo credit: M.E. Schweitzer
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