Response to Comment on "Protein Sequences from Mastodon and Tyrannosaurus rex Revealed by Mass Spectrometry"

Abstract
Endogenous peptide sequences extracted from a 68-million-year-old Tyrannosaurus rex fossil bone and obtained by mass spectrometry have been shown to be statistically significant based on protein database searches using two different search engines and similarity comparisons to authentic tandem mass spectrometry spectra. Specifically, we have validated the sequence GVVGLP(OH)GQR.