Analyses of Soft Tissue from Tyrannosaurus rex Suggest the Presence of Protein

Harvard University, Cambridge, Massachusetts, United States
Science (Impact Factor: 33.61). 05/2007; 316(5822):277-80. DOI: 10.1126/science.1138709
Source: PubMed


We performed multiple analyses of Tyrannosaurus rex (specimen MOR 1125) fibrous cortical and medullary tissues remaining after demineralization. The results indicate that collagen I, the main organic component of bone, has been preserved in low concentrations in these tissues. The findings were independently confirmed by mass spectrometry. We propose a possible chemical pathway that may contribute to this preservation. The presence of endogenous protein in dinosaur bone may validate hypotheses about evolutionary relationships, rates, and patterns of molecular change and degradation, as well as the chemical stability of molecules over time.

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Available from: Mary H Schweitzer,
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    • "The survival of biomolecules in ancient tissues has been of great interest for their potential in recovering phylogenetic information for over 30 years. Since the early 1980s, such protein-derived information was retrieved using immunological approaches, [1] [2] methodology that continues in use even recently, [3] [4] despite notorious issues with false-positive results due to cross-reactivity with likely contaminants (e.g., fungi). [5] The criticism that immunological methods are difficult to apply to fossil samples because the assays are pushed to their limits and are prone to yield false-positive results induced doubt into the authenticity of previous results. "
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    • "Such imprints would not have defined nuclei or other internal cell structures . In addition, antibodies for avian collagen I exhibited an affinity for collagen isolated from T. rex fossils, and this collagen was degraded by collagenase (Schweitzer et al., 2007a). Antibodies with an affinity for both avian and reptile proteins also had affinity for B. canadensis (Schweitzer et al., 2009). "
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    ABSTRACT: Soft fibrillar bone tissues were obtained from a supraorbital horn of Triceratops horridus collected at the Hell Creek Formation in Montana, USA. Soft material was present in pre and post-decalcified bone. Horn material yielded numerous small sheets of lamellar bone matrix. This matrix possessed visible microstructures consistent with lamellar bone osteocytes. Some sheets of soft tissue had multiple layers of intact tissues with osteocyte-like structures featuring filipodial-like interconnections and secondary branching. Both oblate and stellate types of osteocyte-like cells were present in sheets of soft tissues and exhibited organelle-like microstructures. SEM analysis yielded osteocyte-like cells featuring filipodial extensions of 18-20μm in length. Filipodial extensions were delicate and showed no evidence of any permineralization or crystallization artifact and therefore were interpreted to be soft. This is the first report of sheets of soft tissues from Triceratops horn bearing layers of osteocytes, and extends the range and type of dinosaur specimens known to contain non-fossilized material in bone matrix.
    Acta histochemica 02/2013; 115(6). DOI:10.1016/j.acthis.2013.01.001 · 1.71 Impact Factor
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    • "Negative controls of sediments extracted in tandem with dinosaur bone, or buffer blanks, did not produce collagen sequence, and indeed collagen is rarely identified as a contaminant in mass spectrometry analyses. The most parsimonius explanation for all the data presented previously [3] [4] [38] [39] [2] is that collagen is preserved in these ancient tissues. Because we have consistently observed microstructures similar in location and morphology to osteocytes and vessels in demineralized bones from various extinct taxa, deriving from different ages, depositional settings and environments [36] [37] [39], it is also more parsimonious to assume a common source (i.e., endogenous to vertebrate organisms from which they derive) than to invoke identical contaminants in different bones from different environments that consistently produce the same structures; structures that are common in both morphology and immunological response to vertebrate bone components. "
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