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Andrew R. Thompson, West Virginia School of Osteopathic Medicine
Background
Methods
Results
Interregional analysis
Materials
Interregional by sex
LIRV only analysis
Summary of Findings
References
Acknowledgements
LimitaFons and Future Research
LIRV only by sex
An odontometric analysis of interregional biological variaFon in the prehistoric Midwest
●TransiFon from Late Woodland to Mississippian period in the Midwest is characterized by dramaFc shiJs in sociocultural pracFces ●Previous studies in the lower Illinois River valley (LIRV) are inconclusive as to whether these changes were the result of migraFon or shiJs that occurred among staFonary groups:
●The most widely held expectaFon is that groups from the American BoOom (AB), and parFcularly from the Cahokia site, were involved in exchange networks with LIRV groups during the Mississippian period. However, populaFon movement between regions has never been directly evaluated ●Purpose of present study: Examine interregional biological variaFon in the LIRV and AB regions over the Late Woodland to Mississippian transiFon
Study Method Findings Fields (1979) Odontometrics Con5nuity
Droessler (1981) Craniometrics Con5nuity Steadman (1997) Craniometrics Mixed
Raff (2008) mtDNA Mixed
Map of Illinois showing sites used in this study.
●Maximum crown diameters of permanent denFFons ●Intraobserver error tested and found to be within ±0.03mm (see Thompson, 2013)
Odontometrics
Data preparaFon ●ExpectaFon-‐maximizaFon algorithm used to replace missing data: 2425/2930 (83%) of data points present prior to replacement ●Sex standardized using z-‐scores on sex-‐specific pooled matrices ●Final 10 variables: UCMD, UCBL, UP1BL, UM1BL, LCMD, LM2MD, LI2BL, LCBL, LP1BL, and LM1BL
StaFsFcal methods ●R-‐matrix (Relethford and Blangero, 1990) ●Census esFmates made equal, making geneFc distances proporFonal to Mahalanobis distances (Relethford, 1997) ●Distance matrices ploOed using mulFdimensional scaling (MDS)
●Largest distance between Schild LW and Schild Miss ●ConFnuity at Yokem with smallest distance between Fme periods ●More within group variaFon among Late Woodland groups
●During LW period, more between-‐group distance among males ●During Miss period, more between-‐group distance among females ●Largest between-‐group distance in Miss period between females
●Small distances between Cahokia and LIRV Mississippian groups ●Schild LW sFll an outlier ●ESLSQ more similar to Yokem than AB groups
●Schild Miss females similar to individuals at Cahokia ●Schild Miss males tend to be more similar to LIRV groups ●Yokem Miss females plot away from most other groups
●VariaFon among LIRV groups suggests disconFnuity at Schild over the Late Woodland-‐Mississippian transiFon ●Sex-‐based LIRV analysis suggests more female variaFon in Miss period, but possibly from different sources ●Interregional analysis shows strong similarity between Cahokia and Schild Miss individuals ●Sex-‐based interregional analysis suggests increased female movement between Schild and Cahokia, and slightly more regional conFnuity among males ●Yokem Miss females dissimilar to other groups, possibly movement from another region (central Illinois valley?) ●Take home: LW-‐Miss transiFon in LIRV appears to have been somewhat variable with an increase in interregional interacFon, parFcularly among females
●Sample size becomes increasingly small as sex is considered, which required removal of some AB sites in the interregional analysis ●More AB sites needed to beOer assess regional variaFon ●Other forms of data (addiFonal aDNA studies, stronFum isotope, etc.) are needed to evaluate movement/relatedness
I would like to thank the following individuals at for permiMng access to the skeletal remains used in this study: Illinois State Museum-‐Dr. Terrance Mar5n ,Dawn Cobb, and Dee Ann WaT; Indiana University-‐ Dr. Della Cook; Center for Archeological Inves5ga5ons-‐ Dr. Heather Lapham. Special thanks to Della Cook for her input on the development of this research project.
●Droessler, JB. 1981. Craniometry and biological distance : Biocultural con5nuity and change at the Late Woodland -‐ Mississippian interface. Scien5fic papers Northwestern University Archeological Program. Northwestern University Archeological Program, Evanston. ● Fields, BA. 1979. A biological dimension of cultural change: Dental microevolu5on in a prehistoric Amerindian context, Indiana University, Bloomington. ● Raff, J. 2008. An ancient DNA perspec5ve on the prehistory of the lower Illinois Valley, Indiana University, Bloomington. ● Relethford, JH. 1997. Anthropometric data and popula5on history. In Human biologists in the archives: demography, health, nutri5on and gene5cs in historical popula5ons, edited by AD. Herring and AC. Swedlund, pp. 32-‐52. Cambridge University Press, Cambridge. ● Relethford, JH. and J Blangero. 1990.Detec5on of differen5al gene flow from paTerns of quan5ta5ve varia5on. Hum Biol 62(1):5-‐25. ● Steadman, DW. 1997. Popula5on gene5c analysis of regional and interregional prehistoric gene flow in west-‐central Illinois, University of Chicago, Chicago. ● Thompson, AR. 2013. An analysis of biological varia5on during the Late Woodland-‐Mississippian period in the Midwest using the den55on, Indiana University, Bloomington.
Site Region Date (AD) Cultural period
Sample size Male Female
Schild LIRV 800-‐1050 LW 12 24 Schild LIRV 1050-‐1300 Miss 34 26 Yokem LIRV 700-‐1050 LW 15 23 Yokem LIRV 1050-‐1300 Miss 15 18
Mound 72, Cahokia* AB 1000-‐1150 Miss 27 80
Kane Mounds AB 1200-‐1300 Miss 3 5
East St. Louis Stone Quarry
AB 1200-‐1300 Miss 3 7
*Recent studies suggest most individuals in Mound 72 were local to the American BoOom region (Thompson et al., in prep). Feature 229-‐lower omiOed from analyses.
