Metagenomic analyses of 7000 to 5500 years old coprolites excavated from the Torihama shell-mound site in the Japanese archipelago.

Coprolites contain various kinds of ancient DNAs derived from gut micro-organisms, viruses, and foods, which can help to determine the gut environment of ancient peoples. Their genomic information should be helpful in elucidating the interaction between hosts and microbes for thousands of years, as well as characterizing the dietary behaviors of ancient people. We performed shotgun metagenomic sequencing on four coprolites excavated from the Torihama shell-mound site in the Japanese archipelago. The coprolites were found in the layers of the Early Jomon period, corresponding stratigraphically to 7000 to 5500 years ago. After shotgun sequencing, we found that a significant number of reads showed homology with known gut microbe, viruses, and food genomes typically found in the feces of modern humans. We detected reads derived from several types of phages and their host bacteria simultaneously, suggesting the coexistence of viruses and their hosts. The food genomes provide biological evidence for the dietary behavior of the Jomon people, consistent with previous archaeological findings. These results indicate that ancient genomic analysis of coprolites is useful for understanding the gut environment and lifestyle of ancient peoples.