Mary Higby Schweitzer

Mary Higby Schweitzer
Citizenship United States
Nationality American
Fields Paleontology
Alma mater B.S., Communicative Disorders,
Utah State University, 1977
Ph. D., Biology,
Montana State University, 1995

Mary Higby Schweitzer is a paleontologist at North Carolina State University, who is known for leading the groups that discovered the remains of blood cells in dinosaur fossils and later discovered soft tissue remains in the Tyrannosaurus rex specimen MOR 1125,[1][2] as well as evidence that the specimen was a pregnant female when she died.[3] More recently, Schweitzer's work has shown molecular similarities between Tyrannosaurus remains and chickens, providing further evidence of the bird-dinosaur connection.[4]

Biography

Schweitzer earned a B.S. in Communicative Disorders from Utah State University in 1977, and got a Certificate of Secondary Education in Broadfield Science from Montana State University in 1988. Under the direction of mentor Jack Horner, she received her Ph.D. in Biology from Montana State University in 1995.

Mary Higby Schweitzer´s mobile laboratory, Museum of the Rockies, Bozeman (Montana)

She has three children.[5]

Based at the North Carolina State University, Schweitzer is currently researching Molecular Paleontology, molecular diagenesis and taphonomy, evolution of physiological and reproductive strategies in dinosaurs and their bird descendants, and astrobiology.[6]

Discoveries

In 2000, Bob Harmon, chief preparator of paleontology at the Museum of the Rockies, discovered a Tyrannosaurus skeleton in the Hell Creek Formation in Montana. After a two-year retrieval process, Jack Horner, director of the Museum, gave the femur bone to Schweitzer. Schweitzer was able to retrieve proteins from this femur in 2007.[7]

Schweitzer was the first researcher to identify and isolate soft tissues from a 68-million-year-old fossil bone. The soft tissues are collagen, a connective protein. Amino acid sequencing of several samples have shown matches with the known collagens of chickens, frogs, newts and other animals. Prior to Schweitzer’s discovery, the oldest soft tissue recovered from a fossil was less than one million years old.[8] Schweitzer has also isolated organic compounds and antigenic structures in sauropod egg shells.[9] With respect to the significance of her work, Kevin Padian, Curator of Paleontology, University of California Museum of Paleontology, has stated "Chemicals that might degrade in a laboratory over a short period need not do so in a protected natural chemical environment...it's time to readjust our thinking."[8]

Schweitzer previously announced similar discoveries in 1993.[10][11] Since then, the claim of discovering soft tissues in a 68 million year old fossil has been disputed by some molecular biologists. Later research by Kaye et al.[12] published in PLoS ONE (30 July 2008) challenged the claims that the material found is the soft tissue of Tyrannosaurus. A more recent study (October 2010) published in PLoS ONE contradicts the conclusion of Kaye and supports Schweitzer's original conclusion.[13] Evidence for the extraction of short segments of ancient DNA from dinosaur fossils has been reported on two separate occasions.[14] The extraction of protein, soft tissue, remnant cells and organelle-like structures from dinosaur fossils has been confirmed.[15][16][17] Blood-derived porphyrin proteins have also been discovered in a mid Eocene mosquito fossil.[18]

Schweitzer has also discovered that iron particles may play a part in the preservation of soft tissue over geologic time.[19]

References

  1. ↑ Schweitzer, Mary H.; Wittmeyer, Jennifer L.; Horner, John R. (2007). "Soft tissue and cellular preservation in vertebrate skeletal elements from the Cretaceous to the present". Proc Biol Sci. 274 (1607): 183–97. doi:10.1098/rspb.2006.3705. PMC 1685849Freely accessible. PMID 17148248.
  2. ↑ Hitt J (2005). "New discoveries hint there's a lot more in fossil bones than we thought". Discover. October. Archived from the original (– Scholar search) on February 22, 2007. Retrieved 2007-03-05.
  3. ↑ "Geologists Find First Clue To Tyrannosaurus Rex Gender In Bone Tissue". Science Daily. 2005-06-03. Retrieved 2007-03-05.
  4. ↑ Clabby, Catherine (2007-04-13). "T. rex remains yield new treasure". News &Observer. Archived from the original on August 16, 2009. Retrieved 2007-05-04.
  5. ↑ Yeoman, Barry (2006). "Schweitzer's Dangerous Discovery". Discover (April).
  6. ↑ "Schweitzer bio page". NCSU.
  7. ↑ Wilfor, John Noble (April 12, 2007). "Scientists Retrieve Proteins From Dinosaur Bone". New York Times. Retrieved February 8, 2011.
  8. 1 2 Perlman, David (April 13, 2007). "T. Rex Tissue Offers Evolution Insights". San Francisco Chronicle.
  9. ↑ Schweitzer, Mary H.; Chiappe, L; Garrido, A.C; Lowenstein, J.M; Pincus, S.H (April 22, 2005). "Molecular preservation in Late Cretaceous sauropod dinosaur eggshells". Proceedings of the Royal Society B: Biological Sciences. 272 (1565): 775–784. doi:10.1098/rspb.2004.2876.
  10. ↑ Schweitzer, Mary H. (Sep 23, 1993). "Biomolecule Preservation in Tyrannosaurus Rex". Journal of Vertebrate Paleontology. 13: 56A. doi:10.1080/02724634.1993.10011533.
  11. ↑ Schweitzer, Mary H.; Cano, R. J.; Horner, J. R. (Sep 7, 1994). "Multiple Lines of Evidence for the Preservation of Collagen and Other Biomolecules in Undemineralized Bone from Tyrannosaurus Rex". Journal of Vertebrate Paleontology. 14: 45A. doi:10.1080/02724634.1994.10011592.
  12. ↑ Kaye, Thomas G.; Gaugler, Gary; Sawlowicz, Zbigniew (July 30, 2008). Stepanova, Anna, ed. "Dinosaurian Soft Tissues Interpreted as Bacterial Biofilms". PLoS ONE. 3 (7): e2808. doi:10.1371/journal.pone.0002808. PMC 2483347Freely accessible. PMID 18665236.
  13. ↑ Peterson, J. E.; Lenczewski, M. E.; Reed, P. S. (October 2010). Stepanova, Anna, ed. "Influence of Microbial Biofilms on the Preservation of Primary Soft Tissue in Fossil and Extant Archosaurs". PLoS ONE. 5 (10): 13A. doi:10.1371/journal.pone.0013334.
  14. ↑ Schweitzer MH, Zheng W, Cleland TP, Bern M (2012-10-17). "Molecular analyses of dinosaur osteocytes support the presence of endogenous molecules". Bone. 52 (1): 414–23. doi:10.1016/j.bone.2012.10.010. PMID 23085295.
  15. ↑ San Antonio, James D.; Schweitzer, Mary H.; Jensen, Shane T.; Kalluri, Raghu; Buckley, Michael; Orgel, Joseph P. R. O. (2011-06-08). Van Veen, Hendrik W., ed. "Dinosaur Peptides Suggest Mechanisms of Protein Survival". PLoS ONE. 6 (6): e20381. doi:10.1371/journal.pone.0020381. PMC 3110760Freely accessible. PMID 21687667.
  16. ↑ Armitage, Mark H.; Anderson, Kevin L. (2013-02-13). "Soft sheets of fibrillar bone from a fossil of the supraorbital horn of the dinosaur Triceratops horridus". Acta Histochemica. 115 (6): 603–8. doi:10.1016/j.acthis.2013.01.001. PMID 23414624.
  17. ↑ Cleland, Timothy P.; Schroeter, Elena R. (2015-11-23). "Mass Spectrometry and Antibody-Based Characterization of Blood Vessels from Brachylophosaurus Canadensis". Journal of Proteome Research. 14 (12): 5252–5262. doi:10.1021/acs.jproteome.5b00675.
  18. ↑ Greenwalta, Dale E.; Gorevab, Yulia S.; Siljeströmb, Sandra M.; Roseb, Tim; Harbache, Ralph E. (2013-02-13). "Hemoglobin-derived porphyrins preserved in a Middle Eocene blood-engorged mosquito". Proceedings of the National Academy of Sciences. 110 (46): 18496–18500. doi:10.1073/pnas.1310885110. PMC 3831950Freely accessible. PMID 24127577.
  19. ↑ Schweitzer, Mary H.; Zheng, Wenxia; Cleland, Timothy P.; Goodwin, Mark B.; Boatman, Elizabeth; Theil, Elizabeth; Marcus, Matthew A.; Fakra, Sirine C. (January 2014). "A role for iron and oxygen chemistry in preserving soft tissues, cells and molecules from deep time". Proc. R. Soc. B. 281 1777 30132741: 20132741. doi:10.1098/rspb.2013.2741. PMC 3866414Freely accessible. PMID 24285202.
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