Reanalysis of Tyrannosaurus rex Mass Spectra

J Proteome Res. 2009 Sep;8(9):4328-32. doi: 10.1021/pr900349r.


Asara et al. reported the detection of collagen peptides in a 68-million-year-old Tyrannosaurus rex bone by shotgun proteomics. This finding has been called into question as a possible statistical artifact. We reanalyze Asara et al.'s tandem mass spectra using a different search engine and different statistical tools. Our reanalysis shows a sample containing common laboratory contaminants, soil bacteria, and bird-like hemoglobin and collagen.

Publication types

  • Comment
  • Research Support, N.I.H., Extramural

MeSH terms

  • Animals
  • Collagen / chemistry
  • Databases, Protein
  • Dinosaurs*
  • Fossils*
  • Hemoglobins / chemistry
  • Mass Spectrometry / methods*
  • Peptides / analysis
  • Proteomics / methods*


  • Hemoglobins
  • Peptides
  • Collagen