The scientists managed to identify proteins in a bone of a well-preserved 68 million years old Tyrannosaurus rex bone.
The earliest previously identified ancient proteins were from mammoths that died about 300,000 years ago. The oldest confirmed samples of DNA — a more direct bearer of information of molecular evolution, but also more degradable — have come from Neanderthals that lived 30,000 to 50,000 years ago. The extraction of DNA would be necessary for studies in dinosaur genetics and for cloning experiments.
Repeated analysis of the T-rex proteins, the researchers said, uncovered new evidence of a link between dinosaurs and birds, a widely held but contentious hypothesis. Three of the seven reconstructed protein sequences were closely related to chickens. The scientists resisted being drawn into speculation on the likely taste of a T-rex drumstick.
Two research teams are reporting the findings in Friday’s issue of the journal Science. The principal investigators discussed the results with reporters in a teleconference on Wednesday.
Speaking of the doubts she had going into the work, Mary Higby Schweitzer of North Carolina State University, leader of one of the groups, said, “We had always assumed that preservation does not extend to the cellular level” in ancient fossils.
Dr. Schweitzer described several different tests that were conducted on soft tissues found deep inside a tyrannosaur’s femur, or thighbone, excavated in eastern Montana. She reported the surprising tissue discovery two years ago.