Ancient use and long-distance transport of the Four Corners Potato (Solanum jamesii) across the Colorado Plateau: Implications for early stages of domestication

Authors: LOUDERBACK, LISBETH - University Of Utah; WILSON, CINTHIA - University Of California Berkeley; WILKS, STEFANIA - University Of Utah; JOYCE, KALEY - University Of Utah; RICKETT, SARA - University Of Utah; Bamberg, John; DEL RIO, ALFONSO - University Of Wisconsin; PAVLIK, BRUCE - University Of Utah

Submitted to: PLOS ONE
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/14/2025
Publication Date: 1/21/2026
Citation: Louderback, L., Wilson, C., Wilks, S., Joyce, K., Rickett, S., Bamberg, J.B., Del Rio, A., Pavlik, B. 2026. Ancient use and long-distance transport of the Four Corners Potato (Solanum jamesii) across the Colorado Plateau: Implications for early stages of domestication. PLOS ONE. PLoS One 21(1):. https://doi.org/10.1371/journal.pone.0335671.
DOI: https://doi.org/10.1371/journal.pone.0335671

Interpretive Summary: The US Potato Genebank (USPG) at Sturgeon Bay, Wisconsin keeps a collection of all the wild relatives of potato and makes them available to researchers and breeders for improving the crop. To enhance USPG service, we also study the stocks we keep, including their status in wild habitats-- their patterns of genetic diversity and natural history. One potato species, Solanum jamesii (jam), is native to the southwest USA. It has numerous high-value traits not found in the current potato breeding pool. The subject paper on research conducted with partners in Utah describes new evidence that the ancient native Americans actively used and traded jam nearly 11,000 years ago by examining jam starch grains in grinding tools at ancient ruin sites. This discovery will have payoffs to USPG stakeholders by increasing our knowledge of jam natural history, thus giving insights into how to best collect, study, and use samples in the USPG collection.

Technical Abstract: Despite its long history, utilitarian value, and cultural significance to several Indigenous Tribes in the Southwest USA, the extent to which the Four Corners potato (Solanum jamesii Torr.) has been domesticated requires circumscription. Establishing the temporal and spatial dimensions of intentional cultivation would provide an essential component of the domestication argument. This project tests the hypothesis that S. jamesii tubers were processed with ground stone tools from archaeological sites located beyond the natural range of the species, especially where genetic evidence has previously indicated human transport and establishment in gardens. Microbotanical evidence, in the form of starch granules from 401 ground stone tools at 14 archaeological sites, is examined. More than 6,500 starch granules were recovered from the tools; 163 of which were assigned to S. jamesii. Four sites (North Creek Shelter, Long House/Mesa Verde, Pueblo Bonito/Chaco Canyon, and Point of Pines) show consistent use of S. jamesii (ubiquity >18%), as early as 10,900 cal BP, and well into Puebloan times. Three of these sites are located far north of the species’ center of distribution in the Mogollon region, across hundreds of kilometers of the Colorado Plateau, and still support an extant population nearby. This suggests an anthropogenic distribution of S. jamesii across the Four Corners region and a unique cultural identity around the use of this native potato. These findings, combined with ethnographic interviews and nutritional data, provide clear evidence of use in relation to natural and anthropogenic distributions, thereby allowing an assessment of the degree to which these energy-rich, nutritious, and compact tubers were purposely used and transported.