non-metric and metric dental assessment of ancestry in contemporary mexican individuals

125 Pages·2015·2.5 MB·English

NON-METRIC AND METRIC DENTAL ASSESSMENT OF ANCESTRY

IN CONTEMPORARY MEXICAN INDIVIDUALS: AN AID TO

IDENTIFYING UNDOCUMENTED BORDER CROSSERS

____________

A Thesis

Presented

to the Faculty of

California State University, Chico

____________

In Partial Fulfillment

of the Requirements for the Degree

Master of Arts

in

Anthropology

____________

by

Rebecca George

Spring 2015
NON-METRIC AND METRIC DENTAL ASSESSMENT OF ANCESTRY

IN CONTEMPORARY MEXICAN INDIVIDUALS: AN AID TO

IDENTIFYING UNDOCUMENTED BORDER CROSSERS

A Thesis
by
Rebecca George
Spring 2015

APPROVED BY THE DEAN OF GRADUATE STUDIES
AND VICE PROVOST FOR RESEARCH:

_________________________________
Eun K. Park, Ph.D.

APPROVED BY THE GRADUATE ADVISORY COMMITTEE:

______________________________ _________________________________
Guy Q. King, Ph.D. Eric J. Bartelink, Ph.D., Chair
Graduate Coordinator

_________________________________
Beth S. Shook, Ph.D.
ACKNOWLEDGMENTS

This thesis would not have been possible without the work and support of so
many people. First, thank you to my committee chair, Dr. Eric Bartelink. Without your
assistance and guidance, this thesis simply would not have happened. Thank you to my
second committee member, Dr. Beth Shook. Your encouragement during my entire
career at CSU, Chico helped to shape the academic I have become. I thank both of you
for the amount of time and faith you have invested in me and this thesis.
Special thanks are necessary to all the people I encountered along my travels
to complete this thesis. Dr. Heather Edgar, thank you for taking the time to train me, as
well as opening up your collection for my usage. Your students, especially Lexi, Anna,
Kate, and Corey, made my time in Albuquerque an enjoyable experience. Lexi and Mo
O’Donnell, thank you for making me a part of your family during this process. Thank
you to Drs. Traci van Deest and Bruce Anderson at the PCOME for graciously allowed
me access to your laboratory and accommodating every imaginable request. Thanks to
Dr. Laura Fulginiti and Avery at the MCOME for letting me take over your laboratory for
a morning. Thank you to Dr. Kate Spradley at Texas State University for opening the
doors to all of your collections while I was on campus, and for working your hardest to
help me gain access to additional collections. Thanks to Dr. Abigail Meza at the IAA,
UNAM, Mexico City, for helping me with collection access. Many thanks to Sebastián
Santamaria and David Roldan, also at the IAA, for helping me navigate Mexico City and
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for being some of the best people I have come across in my travels. A very special thank
you to Paty Perez for opening your home to me and being a friend in Mexico City when I
needed one the most. Thank you to Dr. Jorge Gómez-Valdes and your students at the
Facultad de Medicina, UNAM, Mexico City for granting me access to your collection. I
look forward to working with you in the future as you continue to build the relationship
between Mexican and American researchers.
My family’s support in this process has been critical, as it has been for my
entire life. Thank you, Mom and Dad, for encouraging me to follow my crazy dreams by
helping me move across the country, travel where I need to, and supporting me along the
way. Thank you, Grandma, for helping me when necessary and being there always.
Thanks, also, to my brother Matt. I love you all.
Numerous of the other professors at CSU, Chico, have provided support and
guidance during my time here. Dr. Colleen Milligan, thank you for being a source of
advice and friendship through the MA process. Dr. P. Willey, thanks for the honest dose
of reality that many of us graduate students need from time to time. To the friends that I
have made since being at CSU, Chico, thank you for your encouragement and guidance.
My physical cohort mates, Aoife Kilmartin and Julia Prince, have been my sounding
board and closest friends during this process – thank you for just being there. Heather
MacInnes, thanks for saving my data! If I have not named you here, know that it is not a
lack of thought or love, I just cannot write a thesis in the acknowledgements to all of you!
Finally, thank you to the Office of Graduate Studies, the Karen Gardner
Research Award, and the Human Identification Laboratory account for funding of this
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thesis. This financial support was just as crucial as any emotional or physical support
received to make this thesis a reality.

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TABLE OF CONTENTS

PAGE

Acknowledgments...................................................................................................... iii

List of Tables.............................................................................................................. viii

List of Figures............................................................................................................. x

Abstract....................................................................................................................... xii

CHAPTER

I. Introduction.............................................................................................. 1
Research Hypothesis Overview.................................................... 3
Organization of Thesis................................................................. 6

II. Background............................................................................................... 7
Introduction.................................................................................. 7
Undocumented Border Crossers................................................... 7
Population Variation in the Human Dentition.............................. 21
Summary....................................................................................... 24

III. Materials and Methods............................................................................. 26
Introduction.................................................................................. 26
Skeletal and Cast Collections....................................................... 27
Data Collection Methods.............................................................. 29
Statistical Methods....................................................................... 45
Summary....................................................................................... 50

IV. Non-Metric Results.................................................................................. 52

Introduction.................................................................................. 52
Intraobserver Error....................................................................... 52
Interobserver Error....................................................................... 53

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CHAPTER PAGE

Region-of-Origin Trait Distributions for the Skeletal Samples... 55
Logistic Regression Analysis....................................................... 62
Mean Measure of Divergence...................................................... 64
Summary....................................................................................... 66

V. Metric Results........................................................................................... 69
Introduction.................................................................................. 69
Intraobserver Error....................................................................... 69
Interobserver Error....................................................................... 70
Sex Differences............................................................................ 71
Morris (1986) Occlusal Polygon Method..................................... 74
Discriminant Function Analysis................................................... 77
Summary....................................................................................... 85

VI. Discussion and Conclusion....................................................................... 88

Introduction.................................................................................. 88
Discussion..................................................................................... 88
Conclusion.................................................................................... 99

References Cited......................................................................................................... 102
Appendix

A. Adult Dentition: Nonmetrics..................................................................... 110

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LIST OF TABLES

TABLE PAGE

1. Intraobserver Error Cohen’s Kappa Results............................................. 54

2. Interobserver Error Cohen’s Kappa Results............................................. 55

3. Sample Frequencies by Region-of-Origin................................................ 56

4. Pearson’s Chi-square and Fisher’s Exact Results of Traits
Present (SWH and Mexican)............................................................ 58

5. Pearson’s Chi-Square and Fisher’s Exact Results of Traits
Present (SWH and all UBC)............................................................. 60

6. Pearson’s Chi-Square and Fisher’s Exact Results of Traits
Present (Mexican and all UBC)........................................................ 61

7. Logistic Regression Model Performance................................................. 63

8. MMD Results for Biodistance among the Region-of-Origin Groups...... 65

9. Paired t-test Results for Intraobserver Error............................................. 70

10. Paired t-test Results for Interobserver Error............................................. 71

11. Student’s t-test for Sex Differences in the Maxillary Dentition............... 72

12. Student’s t-test for Sex Differences in the Mandibular Dentition............ 73

13. Region-of-Origin Samples for Occlusal Polygon Assessment................. 75

14. Modified Morris (1986) Occlusal Polygon Results – Maxillary
Dentition (in mm2)............................................................................ 76

15. Modified Morris (1986) Occlusal Polygon Results – Mandibular
Dentition (in mm2)............................................................................ 76

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TABLE PAGE

16. Mean Occlusal Polygon ANOVA Results with Tukey’s
Correction – Maxillary Dentition...................................................... 77

17. Mean Occlusal Polygon ANOVA Results with Tukey’s
Correction – Mandibular Dentition................................................... 77

18. Maxillary Dentition Group Centroids per Function................................. 81

19. Maxillary Dentition DFA Classification Results (in %).......................... 82

20. Mandibular Dentition Group Centroids per Function.............................. 83

21. Mandibular Dentition DFA Classification Results (in %)....................... 84

22. Pooled Dentition Group Centroids per Function...................................... 85

23. Pooled DFA Classification Results (in %)............................................... 86

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LIST OF FIGURES

FIGURE PAGE

1. Map Highlighting the Locations of Reference and Study
Collections Used in This Thesis......................................................... 4

2. An Example of Bilaterally Winged Central Maxillary Incisors............... 31

3. Dental Cast Used to Score Labial Curvature............................................ 31

4. Dental Cast Used to Score Maxillary Central Incisor Shoveling............. 32

5. Dental Cast Used to Score Maxillary Lateral Incisor and
Canine Shoveling................................................................................ 32

6. Dental Cast Used to Score Mandibular Incisor Shoveling....................... 33

7. Dental Cast Used to Score Double Shoveling.......................................... 33

8. An Example of an Interruption Groove on a Right Lateral
Maxillary Incisor................................................................................. 34

9. Dental Cast Used to Score Tuberculum Dentale...................................... 35

10. Dental Cast Used to Score Canine Mesial Ridge..................................... 35

11. Dental Cast Used to Score the Canine Distal Accessory Ridge
in the Maxilla...................................................................................... 36

12. Dental Cast Used to Score the Canine Distal Accessory Ridge
in the Mandible................................................................................... 36

13. Examples of Both Mesial and Distal Premolar Accessory
Cusps Are Highlighted in the Maxilla................................................ 37

14. Dental Cast Used to Score Maxillary Premolar Accessory Ridge............ 37

15. Dental Cast Used to Score the Metacone.................................................. 38
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