On 2013 Nov 04, Steven Salzberg commented:

This is the first in a series of reports, all coming from the same lab, claiming to have found extant protein sequences in 68-million-year-old fossils. The technical comments published subsequently in Science, and comments published elsewhere, showed convincingly that these results were likely due to contamination or simply misinterpretation. Buckley et al (http://www.ncbi.nlm.nih.gov/pubmed/18174420) show that the amino acids in the mass spec data appear to be modern. Pevzner et al. (http://www.ncbi.nlm.nih.gov/pubmed/18719266) explain that they may represent statistical artifacts. Others have also published results showing that the "soft tissue" reported by Schweitzer and colleagues here and elsewhere is consistent with a bacterial biofilm.

These results have never been replicated by anyone other than the original authors. The prior likelihood of extant proteins or soft tissue in T. rex fossils is near zero, and the evidence supplied here is consistent with several other, far more likely interpretations. Nonetheless, these authors (but no others) have continued to publish papers asserting that they've found dinosaur peptides.

On 2013 Nov 04, Steven Salzberg commented:

This is the first in a series of reports, all coming from the same lab, claiming to have found extant protein sequences in 68-million-year-old fossils. The technical comments published subsequently in Science, and comments published elsewhere, showed convincingly that these results were likely due to contamination or simply misinterpretation. Buckley et al (http://www.ncbi.nlm.nih.gov/pubmed/18174420) show that the amino acids in the mass spec data appear to be modern. Pevzner et al. (http://www.ncbi.nlm.nih.gov/pubmed/18719266) explain that they may represent statistical artifacts. Others have also published results showing that the "soft tissue" reported by Schweitzer and colleagues here and elsewhere is consistent with a bacterial biofilm.

These results have never been replicated by anyone other than the original authors. The prior likelihood of extant proteins or soft tissue in T. rex fossils is near zero, and the evidence supplied here is consistent with several other, far more likely interpretations. Nonetheless, these authors (but no others) have continued to publish papers asserting that they've found dinosaur peptides.