Mississippian kinship and the organization of the Koger's Island cemetery
The assumption that Mississippian societies were matrilineal and exogamous has not been tested. This pattern of kin group organization may be examined archaeologically through biodistance studies of cranial and dental remains. This study focuses on the Mississippian cemetery of Koger's Island to determine if average genetic homogeneity within spatial groupings at Koger's Island is greater than that between groups, and further, if there is greater homogeneity among females within spatial groups than males. If confirmed, it may be inferred that kin groups were both matrilineal and exogamous. Confirming matrilineality and exogamy within this cemetery population would contribute to a growing awareness that forms of kin groups were not uniform across the Mississippian Southeast. Visually, the Koger's Island burials appear to be arranged in rows. In previous studies the burials have been compared in terms of grave goods, age, sex, and trauma, but no prior biodistance study has been conducted to determine biological relationships within the cemetery. Previous research by Peebles (1971) suggested that rows may have been delineated by factors other than kinship. Marcoux (2010), in contrast, concluded that kinship may have been an important organizing principle on the island, but that the cemetery was not arranged in discrete rows on that basis (Marcoux 2010). In, this study, biodistances were calculated for each pair of individuals by mathematically combining 211 variables using a distance metric. Four different spatial configurations were tested to see if biodistance played a role in their formation. Cluster analysis was then used to examine overall patterning within a Gower's distance matrix. Clusters of individuals were predicted to fall into distinct spatial groups, indicating that individuals were interred with biological kin. Also, females within clusters were predicted to have greater homogeneity than males indicating the exogamous matrilineality expected for this Mississippian group. While clusters did not map so neatly as hypothesized, evidence was found to indicate that a biological component played some role in the Koger's Island cemetery burial organization.