Dietary DNA Analysis of Mississippian Dog Coprolites

Traditional methods for assessing diet of animal coprolite samples include targeted PCR and sequencing of specific genes. While useful for species identification, focusing on a single gene region disregards the plant and animal DNA fragments that are from other parts of the genome. Here we used next-generation sequencing methods to sequence DNA from coprolite samples from Terminal Late Woodland and Mississippian dogs from the Janey B. Goode site in Southern Illinois. BLAST searches were used to compare the sequenced reads to complete mitochondrial and chloroplast genomes of plants and animals. Analysis of the coprolites demonstrates that the dogs at Janey B. Goode ate an animal diet of fish, which correlates with previous zooarchaeological analyses of coprolite contents, and a more varied plant diet that included sunflowers, and, in some of the dogs, maize. The presence of maize in the diet of the dogs is significant because maize was an important part of Mississippian culture, and determining the age of the coprolites can help assess when maize arrived to southern Illinois, the timing of which has not yet been clarified. This research demonstrates that next-generation sequencing of coprolites can yield more diverse dietary information than targeted PCR methods.