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Biological Distance and the African American Dentition

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Biological Distance and the African American Dentition BIOLOGICAL DISTANCE AND THE AFRICAN AMERICAN DENTITION DISSERTATION Presented in Partial Fulfillment of the Requirements for the Degree Doctor of Philosophy in the Graduate School of The Ohio State University By Heather Joy Hecht Edgar, M.A. * * * * * The Ohio State University 2002 Dissertation Committee: Approved by Professor Paul Sciulli, Adviser Associate Professor Jeffrey McKee ___________________________ Adviser Assistant Professor Ivy Pike Anthropology Graduate Program Professor Edward Harris Copyright 2002 ABSTRACT Gene flow occurs whenever two human populations come in contact. African Americans are the result of gene flow between two biologically disparate groups: West Africans and Americans of European descent. This project utilized characteristics of dental morphology to trace genetic relationships among these three groups. Dental morphological traits are useful for this purpose because they are heritable, do not remodel during life (although they can be lost to wear or pathology), and can be compared equally among samples from past and present populations. The results of this research provide new knowledge about human microevolution in a biocultural setting. By analyzing observations from a variety of samples from African Americans, European Americans, West Africans, and western Europeans, conclusions were made on patterns of genetic change through time and space. The specific hypothesis addressed is that since gene flow has been continuous among West Africans, African Americans, and European Americans in the American colonies and subsequently in the United States, the more recent a sample of African Americans observed, the more they tend toward the average, genetically, of West Africans and Europeans. Dental characteristics reflect this heritage and the pattern of temporally limited genetic similarities. In addition to testing this hypothesis, several predictions were made and tested regarding the historical patterns of admixture in African ii Americans. These predictions involved whether gene flow has occurred at a constant rate, whether African Americans with greater admixture were more likely to take part in the Great Migration, and whether the dental morphology of the Gullah of South Carolina is especially like their West African ancestors. The results of this research indicate that while admixture of European American genes into the African American gene pool has been continuous over the last 350 years, it has not occurred at a constant rate. Cultural trends and historical events such as the Civil War and the Jim Crow era affected the rate of admixture. A final product of the current research is a series of probability tables that can be used to determine the likely racial affiliation of an unknown individual. These tables are useful in historic archaeological and forensic settings. iii Dedicated to my mother. She said I could be the educated one. iv ACKNOWLEDGMENTS My thanks go first to my advisor, Paul W. Sciulli, who guided me though the doctoral process with insight, humor, and wisdom. I am also grateful for the efforts of my committee members Edward F. Harris, Jeffrey K. McKee, and Ivy L. Pike. I appreciate all of your advice and your work on my behalf. Research for this project was conducted at several institutions. I owe a debt of gratitude to the following people for allowing access to their collections: Ken Mowbray, Ian Tattersall, and Nell Murphy at the American Museum of Natural History, Brenda Baker at Arizona State University, B. Holly Broadbent and Mike at Case Western Reserve University, Lyman Jellema and Bruce Latimer at the Cleveland Museum of Natural History, Lenore Barbian and Paul Sledzik at the National Museum of Health and Medicine, David Hunt at the National Museum of Natural History, Louise Humphrey and Ron Kruszynski at the Natural History Museum in London, Lisa Anderson at the State Museum of New York, and Edward Harris at the University of Tennessee Health Science Center. Thanks also go to Jerome Rose and Ted Rathbun, who sent collections to me for analysis. I am especially appreciative to Renee Menegaz-Bock, who donated her large dental cast collection, including the Gullah sample used in the current research, to Ohio v State University, and to the late Bill Pollitzer, who urged be to contact Dr. Menegaz- Bock about her collections. My family, friends, and fellow students have been incredibly supportive throughout this process, I can't thank you enough. It is for my husband Bruce that I am most thankful. You already know that your strength, support and love means more than I can ever say. This research was supported by the National Science Foundation (Dissertation Improvement Grant #0087400), The American Museum of Natural History, and the Ohio State University Graduate Student Alumni Research Award. vi VITA May 22, 1969 . Born - Bay Shore, New York, USA 1990 . B.A. Anthropology, University of Nevada, Las Vegas 1994 . M.A. Anthropology, Arizona State University 1991-1993 . Research Assistant / Bioarchaeologist, Arizona State University 1993-1995 . Osteologist, University of Texas Southwestern Medical Center 1997-2001 . Graduate Teaching Associate, The Ohio State University 2001 - present . Visiting Instructor, College of Wooster, Wooster Ohio PUBLICATIONS Edgar HJH. 2001. Dental Anthropology at Ohio State University. Dental Anthropology Journal 15:1(12-13). Condon CG, Becker JL, Edgar HJH, Davidson JM, Hoffman JR, Kalima P, Kysar D, Moorhead S, Owens VM, Condon K. 1998. Freedman's Cemetery Site 41DL 316 Dallas, Texas: Assessments of Sex, Age at Death, Stature, and Date of Interment for Excavated Burials. Texas Department of Transportation, Environmental Affairs Division, Archeology Studies Program, Report No. 9. vii Edgar HJH. 1997. Paleopathology of the Wizard’s Beach Man (AHUR 2023) and the Spirit Cave Mummy (AHUR 2064). Nevada Historical Quarterly, 40:1(57-61). Edgar HJH, Barette TS. 2000. Comparative human and mammalian taphonomy at the Richards Site, Ohio. American Journal of Physical Anthropology Supplement 30, page 144. Barette TS, Edgar HJH, Lease LR. 1999. Possible treponematosis in pre-contact Ohio. Paleopathology Association Papers, 26th Annual Meeting Issue. Edgar HJH. 1998. Ritual destruction of human remains: A case in Southeast Ohio. American Journal of Physical Anthropology Supplement 26, page 105. Edgar HJH. 1997. Paleopathology of two Pleistocene skeletons from the Great Basin. Paleopathology Association Papers, 24th Annual Meeting Issue. Edgar HJH, Condon KW, Condon CG. 1995. Degenerative vertebral pathology in a historic skeletal series. American Journal of Physical Anthropology, Supplement 20, page 87. Edgar HJH. 1994. Paleopathology of the Basketmaker II Virgin Anasazi. Paleopathology Association Papers, 21st Annual Meeting Issue. Merbs CF, Edgar HJH, Buck A. 1994. Degenerative spondylolisthesis: Its nature and significance. Paleopathology Association Papers, 21st Annual Meeting Issue. Hecht HJ. 1992. Paleopathology of Basketmaker II Anasazi from Kane County, Utah. Paleopathology Association Papers, 19th Annual Meeting Issue. FIELD OF STUDY Major Field: Anthropology viii TABLE OF CONTENTS Page Abstract . .ii Dedication . iv Acknowledgments . .v Vita . .vii List of Tables . xii List of Figures . xvi Chapters: Introduction . .1 A model of African American admixture . 3 A definition of race . 5 The utility of race as a descriptor for human variation . 9 Research design . 11 Theoretical considerations . 11 Measures of biological distance . 12 Forensic applications . 16 Predictions . .18 Background . .20 Dental anthropology . 21 Dental morphology studies . .22 Geographical dental patterns . .28 Why are there races? . 31 The biosocial history of African Americans . 33 Factors affecting admixture in African Americans . .33 Studies of admixture . .36 A note about DNA . 41 Estimates of Native American admixture in African Americans . .41 ix Estimates of European admixture in African Americans . .42 Material . .45 Sample descriptions . 46 Early period American samples . 46 Middle period American samples . .47 Late period American samples . 50 West African samples . .51 South African sample . 52 Western European samples . .52 Methods . .56 Morphological observations. .56 Statistical methods . 60 Intra-observer error . .60 Comparing data from observations on different materials . .62 Combining observations . .62 Choosing breakpoints . 64 Measures of biological affinity . .67 Other statistical techniques . .69 Results . .74 Trait frequencies . .74 Limitations on observations . 75 Low frequency traits . .76 Traits of forensic utility . 79 Measures of biological affinity . .80 Determining which traits were useful for each analysis . .80 Mean measure of divergence . 82 Pseudo-Mahalanobis' D2 . .97 Procrustes analysis . 100 Forensic analysis . ..
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