Molecular Phylogenetics of Mastodon and Tyrannosaurus rex

Science 25 April 2008

Vol. 320. no. 5875, p. 499
DOI: 10.1126/science.1154284

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Chris L. Organ,^1,2 Mary H. Schweitzer,^3,4 Wenxia Zheng,³ Lisa M. Freimark,⁵ Lewis C. Cantley,^5,6 John M. Asara^5,6*

We report a molecular phylogeny for a nonavian dinosaur, extending our knowledge of trait evolution within nonavian dinosaurs into the macromolecular level of biological organization. Fragments of collagen 1(I) and 2(I) proteins extracted from fossil bones of Tyrannosaurus rex and Mammut americanum (mastodon) were analyzed with a variety of phylogenetic methods. Despite missing sequence data, the mastodon groups with elephant and the T. rex groups with birds, consistent with predictions based on genetic and morphological data for mastodon and on morphological data for T. rex. Our findings suggest that molecular data from long-extinct organisms may have the potential for resolving relationships at critical areas in the vertebrate evolutionary tree that have, so far, been phylogenetically intractable.

¹ Harvard University, Cambridge, MA 02138, USA.
² Museum of Comparative Zoology, Cambridge, MA 02138, USA.
³ North Carolina State University, Raleigh, NC 27695, USA.
⁴ North Carolina Museum of Natural Sciences, Raleigh, NC 27601, USA.
⁵ Beth Israel Deaconess Medical Center, Boston, MA 02115, USA.
⁶ Harvard Medical School, Boston, MA 02115, USA.

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Interpreting sequences from mastodon and T. rex.

Science 7 April 2007:
Vol. 317. no. 5843, pp. 1324-5.

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Protein Sequences from Mastodon and Tyrannosaurus Rex Revealed by Mass Spectrometry

Science 13 April 2007:
Vol. 316. no. 5822, pp. 280 - 285
DOI: 10.1126/science.1137614

Fossilized bones from extinct taxa harbor the potential for obtaining protein or DNA sequences that could reveal evolutionary links to extant species. We used mass spectrometry to obtain protein sequences from bones of a 160,000- to 600,000-year-old extinct mastodon (Mammut americanum) and a 68-million-year-old dinosaur (Tyrannosaurus rex). The presence of T. rex sequences indicates that their peptide bonds were remarkably stable. Mass spectrometry can thus be used to determine unique sequences from ancient organisms from peptide fragmentation patterns, a valuable tool to study the evolution and adaptation of ancient taxa from which genomic sequences are unlikely to be obtained.

¹ Division of Signal Transduction, Beth Israel Deaconess Medical Center, Boston, MA 02115, USA.
² Department of Pathology, Harvard Medical School, Boston, MA 02115, USA; North Carolina Museum of Natural Sciences, Raleigh, NC 27601, USA; and Museum of the Rockies, Montana State University, Bozeman, MT 59717, USA.
³ Department of Marine, Earth and Atmospheric Sciences, North Carolina State University, Raleigh, NC 27695, USA.
⁴ Department of Systems Biology, Harvard Medical School, Boston, MA 02115, USA.

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

Science 13 April 2007:
Vol. 316. no. 5822, pp. 277 - 280
DOI: 10.1126/science.1138709

Mary Higby Schweitzer^1,2,3* Zhiyong Suo⁴ Recep Avci⁴ John M. Asara^5,6 Mark A. Allen⁷ Fernando Teran Arce^4,8 John R. Horner³

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.

¹ Department of Marine, Earth and Atmospheric Sciences, North Carolina State University, Raleigh, NC 27695, USA.
² North Carolina Museum of Natural Sciences, Raleigh, NC 27601, USA.
³ Museum of the Rockies, Montana State University, Bozeman, MT 59717, USA.
⁴ Image and Chemical Analysis Laboratory Facility, Department of Physics, Montana State University, Bozeman, MT 59717, USA.
⁵ Division of Signal Transduction, Beth Israel Deaconess Medical Center, Boston, MA 02115, USA.
⁶ Department of Pathology, Harvard Medical School, Boston, MA 02115, USA.
⁷ Department of Chemistry and Biochemistry, Montana State University, Bozeman, MT 59717, USA.
⁸ Center for Nanomedicine, Pulmonary and Critical Care Medicine, Department of Medicine, University of Chicago, Chicago, IL 60637, USA.

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