The population shuffle in the central Illinois valley: A diachronic model of Mississippian biocultural interactions

Abstract

A new population genetics method is applied to discriminate between processes of extraregional gene flow and intraregional biological continuity within and among three temporally sequential prehistoric Native American cultures in the central Illinois valley. Within a population genetics framework, the impact of regional and interregional cultural changes on local population structure can be quantified and the magnitude of biocultural interaction can be inferred. The results suggest that population structure within the region was relatively unaffected by the cultural transition from Late Woodland to Mississippian or by significant interregional sociopolitical changes in neighboring regions later in the Mississippian period. Finally, a Bold Counselor Phase Oneota population was morphologically distinct from Mississippians, supporting the archaeological model that this Oneota group was an intrusive, frontier population from the upper Mississippi valley. A population genetic approach is highly recommended over traditional biodistance analyses to formally address how past demographic and biocultural processes affected local population structures.