Dinosaurs are more closely related to birds than reptiles, protein extracted from a Tyrannosaurus rex bone suggests. T. rex collagen, the main protein in bones, is similar to chicken and ostrich collagen but much different than material from alligators and lizards, scientists say. The findings could remap the evolutionary tree according to molecular data rather than bone structure, the Washington Post reports.
DNA usually can't be extracted from specimens more than 100,000 years old, moving some critics to wonder whether the 68-million-year-old T. rex sample was contaminated. But the team says it is all but certain the findings are legit. They will be published tomorrow in the journal Science.