The genetic prehistory of the lower Illinois River valley: An ancient DNA analysis of Yokem Mounds 1-

Yokem Mounds and its neighboring lower Illinois River valley sites were part of a dramatic cultural shift that occurred during the transition from the Late Woodland period (A.D. 400-1050) to the Mississippian period (A.D. 1050-1400) of Illinois prehistory. Evident changes in diet, burial treatment, and material culture accompanied this transition at Yokem Mounds. What remains unknown is whether the transition co-occurred with a population displacement by originators of the Mississippian culture, the Cahokians, or other Mississippian immigrants. My ancient DNA analysis of Yokem Mounds 1-5 tackled this question, as well as described other cultural behaviors in order to identify additional impacts of the Mississippian culture.;I typed the mitochondrial DNA of 21 Late Woodland and 23 Mississippian individuals and placed the results within the context of previous genetic studies of the lower Illinois River valley and other ancient Midwest populations. I determined that there was genetic continuity between the Late Woodland and Mississippian populations, both populations practiced patrilocal postmarital residence patterns, and neither had burial patterns organized by matrilines. The differences in maize consumption as determined by stable isotopic signatures amongst the Late Woodland population were not associated with matrilineal familial diet preference. The population genetic analysis identified genetic connections between Yokem Mounds and contemporaneous populations at Schild Cemetery, Orendorf, and Angel Mounds; but Yokem Mounds was significantly different from the Oneota population at Norris Farms #36. Additionally, Mycobacterium tuberculosis Complex DNA was recovered from eleven individuals from Yokem Mounds and Schild Cemetery. Notably, two of these individuals date to the Middle Woodland period (100 B.C.-A.D. 400), which is the earliest identification of Mycobacterium tuberculosis complex DNA in the lower Illinois River valley. Overall, this research further expands our understanding of Native American prehistory and the demographic changes that occurred prior to European contact.