Researchers have extracted collagen protein from a 68-million-year-old Tyrannosaurus rex femur, which two years ago was revealed to have soft tissue. Chemical analysis of the protein yielded seven sequences of about 10 to 20 amino acids in length. Three sequences matched collagen peptide scripts from chickens, one matched a frog and another a salamander; the other two matched multiple organisms, including chickens and salamanders. The results strengthen the bird-dinosaur connection and jettison the belief that ancient fossils could not provide protein samples for study (sorry, Jurassic Park fans—any genetic material degraded long ago). The findings and the techniques used to uncover them should clarify the relations between extinct species and modern-day animals and reveal more about “patterns of molecular change and the rates and directions of molecular evolution,” says Mary Schweitzer of North Carolina State University, who reports the work with her colleagues in the April 13 Science.
This article was originally published with the title "Collagen from T. Rex" in Scientific American 296, 6, 38 (June 2007)