Announced in the May 1 issue of Science, the discovery in an 80-million-year-old hadrosaur showed that a previous, similar find in a 68-million-year-old Tyrannosaurus rex wasn't a fluke, said a research team led by North Carolina State University, Harvard University, Harvard Medical School and Beth Israel Deaconess Medical Center.
Lead author of the Science article was Mary Higby Schweitzer of NC State and the NC Museum of Natural History, a Helena native and former MSU graduate student. MSU co-authors were Recep Avci and Zhiyong Suo from the Imaging and Chemical Analysis Laboratory, and Jack Horner, the Ameya Preserve curator of paleontology at the Museum of the Rockies. A former MSU graduate student, Chris Organ of Harvard University, was also a co-author.
Schweitzer and a previous team announced in 2007 that they had found collagen in the thigh bone of a T. rex from the Jordan area of eastern Montana. Collagen is the main organic compound found in bone. Responding to skeptics who doubted that protein could survive for 68 million years, Schweitzer's team looked for another well-preserved dinosaur that could further support their claims.
"We were looking for something that had the potential of producing more protein and more soft tissue like the T. rex," Horner said. "We just figured we would go to the best place, go to the place where the best bone is exposed."
The search took Horner's field crew to state land around Malta, an area that had yielded several well-preserved dinosaurs in the past, Horner said. There, under about 20 feet of sandstone in the Judith River formation, the paleontologists found the leg of a duck-billed dinosaur. They excavated the hadrosaur fossil in 2007.
The Science article said the scientists left some of the sediments around the bone to keep degradation to a minimum, then covered the fossil with plaster and drove it to Bozeman. Working in Horner's paleontology lab, Schweitzer collected bone and sediment samples with sterile instruments, wrapped the samples in layers of foil and placed them in sealed jars. She then sent samples to five laboratories, including ICAL at MSU.
The labs conducted tests independently that supported the idea that the hadrosaur, like the T. rex, contained transparent, hollow, flexible vessels, according to the Science article. Some vessels contained cell-like structures, while others contained a red substance that looked like degraded blood from an ostrich.
An NC State press release quoted Schweitzer as saying that, "We used improved methodology with better instrumentation, did more experiments and had the results verified by other independent labs. These data not only build upon what we got from the T. rex, but they take the research even further."
The NC State release said the researchers examined the bones microscopically with transmitted light and electron microscopes to confirm that they looked like collagen. They also tested them against antibodies that are known to react with collagen and other proteins. They analyzed the specimens with a new mass spectrometer capable of producing protein sequences with much greater resolution than the one used previously. With the mass spectrometer, co-author John Asara from the Beth Israel Deaconess Medical Center and Harvard Medical School was able to identify eight collagen peptides from the hadrosaur.
Avci, director of ICAL, said scientists who reviewed the Science article before publication were concerned initially that impurities could have gotten into the specimens. Some of the tests used chemicals to extract biological materials from the bone fragments. The reviewers approved publication, however, after learning that the structures were evident even during direct, non-invasive, examination with the mass spectrometer.
Schweitzer said, "This crucial piece of the work was done by Avci and Suo, using state-of-the-art technology that isolated a particular, diagnostic amino acid directly to the dinosaur tissues rather than to chemical extracts."
"It's exciting" Avci said. "This is the beginning of the story, not the end."
Horner said he doesn't know if the latest find will satisfy everyone who doubts that protein can survive for millions of years, but commented, "The nay-sayers can only say the world is flat for so long. It will be interesting to see what they say."
Science is a weekly journal that publishes scientific news, as well as the most significant breakthroughs in global research. It is the world's largest circulation journal for a general science audience.
For a related article, see:
"Eastern Montana dinosaur now yields protein that's 68 million years old" at http://www.montana.edu/cpa/news/nwview.php?article=4777&log
Evelyn Boswell, (406) 994-5135 or firstname.lastname@example.org