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 known for leading the groups which 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 in 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. She received her Ph.D., in Biology from Montana State University in 1995. She has three children.^[5] Schweitzer is a devout Christian who believes strongly in the synergy of the Christian faith and the truth of empirical science.^[6]

Schweitzer is currently researching Molecular Paleontology, molecular diagenesis and taphonomy, evolution of physiological and reproductive strategies in dinosaurs and their bird descendants, and astrobiology.^[7] She is also working with NASA scientists to look for trace evidences of past life on other bodies in the solar system.^[8]

Discoveries

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.^[9] Schweitzer has also isolated organic compounds and antigenic structures in sauropod egg shells.^[10] 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."^[9]

Schweitzer first publicly announced her discovery in 1993.^[11][12] Since then, the claim of discovering soft tissues in a 68 million year old fossil has been disputed by some molecular biologists. The authenticity of her discovery, however, is now generally not accepted in the scientific community^{[citation needed]}. Newer research, published in PloS One (30 July 2008), has challenged the claims that the material found is the soft tissue of Tyrannosaurus. Thomas Kaye of the University of Washington and his co-authors contend that what was really inside the tyrannosaur bone was slimy biofilm created by bacteria that coated the voids once occupied by blood vessels and cells. The researchers assumed that what previously had been identified as remnants of blood cells, because of the presence of iron, were actually framboids, microscopic mineral spheres bearing iron. They found similar spheres in a variety of other fossils from various periods, including an ammonite. In the ammonite they found the spheres in a place where the iron they contain could not have had any relationship to the presence of blood. The successful extraction of ancient DNA from dinosaur fossils has been reported on two separate occasions, but, upon further inspection and peer review, neither of these reports could be confirmed. A more recent study (October 2010) published in PloS One contradicts the conclusion of Kaye and supports Schweitzer's original conclusion.^[13]

References

1. ^ Schweitzer M, Wittmeyer J, Horner J (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 1685849. PMID 17148248. http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=1685849. 
2. ^ Hitt J (2005). "New discoveries hint there's a lot more in fossil bones than we thought" (– ^{Scholar search}). Discover October. Archived from the original on February 22, 2007. http://web.archive.org/web/20070222105935/http://www.discover.com/issues/oct-05/features/paleontology/. Retrieved 2007-03-05. ^{[dead link]}
3. ^ "Geologists Find First Clue To Tyrannosaurus Rex Gender In Bone Tissue". Science Daily. 2005-06-03. http://www.sciencedaily.com/releases/2005/06/050602173113.htm. Retrieved 2007-03-05. 
4. ^ Clabby, Catherine (2007-04-13). "T. rex remains yield new treasure". News &Observer. http://www.newsobserver.com/102/story/563694.html. Retrieved 2007-05-04. ^{[dead link]}
5. ^ Yeoman, Barry (2006). "Schweitzer's Dangerous Discovery". Discover (April). http://discovermagazine.com/2006/apr/dinosaur-dna. 
6. ^ American Scientific Affiliation, http://www.asa3.org
7. ^ Schweitzer bio page at NCSU
8. ^ Fields, Helen (2006). "Dinosaur Shocker". Smithsonian (May). http://www.smithsonianmagazine.com/issues/2006/may/dinosaur.php. 
9. ^ ^{a b} David Perlman, T. Rex Tissue Offers Evolution Insights, San Francisco Chronicle, April 13, 2007
10. ^ M H Schweitzer , L Chiappe , A C Garrido , J M Lowenstein , S H Pincus "Molecular preservation in Late Cretaceous sauropod dinosaur eggshells" Proc Biol Sci. 2005 Apr 22;272 (1565):775-84
11. ^ Schweitzer, Mary H. (Sept. 23, 1993). "Biomolecule Preservation in Tyrannosaurus Rex". Journal of Vertebrate Paleontology 13: 56A. 
12. ^ Schweitzer, MH; Cano, RJ; Horner, JR (Sept. 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. 
13. ^ Peterson, JE; Lenczewski, ME; Reed, PS (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. 

External links

• Barry Yeoman, Schweitzer's Dangerous Discovery, Discover.
• North Carolina State University Faculty Page

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