Ancient people carried a wild potato across the American Southwest

The findings suggest that Indigenous communities played an active role in shaping the plant's future. By moving and using this wild potato, they may have begun the earliest stages of domestication while also building a distinctive cultural tradition in the Four Corners region.

The Four Corners Potato and Its Ancient Use

The plant at the center of the study is known as the Four Corners potato (Solanum jamesii). It is a small but hardy and nutritious wild potato that still grows across southwestern North America today, ranging from southern Utah and Colorado into northern Mexico.

To learn how the potato was used in the past, researchers examined ground stone tools from 14 archaeological sites. These sites span a wide stretch of time, from several hundred to many thousands of years old. The tools were tested for tiny starch granules left behind when plants were processed for food.

Stone Tools and Genetic Clues Tell the Story

Starch from the Four Corners potato was identified on tools from nine of the sites. Some of the evidence dates back as far as 10,900 cal BP. Most of these locations sit near the modern northern edge of the potato's range, along the borders of Colorado, Utah, Arizona, and New Mexico.

Earlier genetic research adds another layer of evidence. Some living populations of the Four Corners potato in this northern area show strong genetic signs that they originated much farther south. This supports the idea that people carried the plant across the region, extending its range north into Utah and Colorado, where it still grows today.

Early Domestication and Living Cultural Traditions

Researchers note that repeated use of a plant and its movement beyond its natural range are both key indicators of early domestication. In this case, those behaviors appear to have begun thousands of years ago.

Even today, the Four Corners potato holds cultural importance for Indigenous communities. Alongside laboratory work, the research team interviewed 15 Navajo (Diné) elders. These conversations confirmed that the wild potato remains known, eaten, and used for spiritual purposes.

Lisbeth Louderback adds: "By combining new archaeobotanical data and elder interviews with transport patterns identified by genetic sequencing of the Four Corners potato, we have defined an anthropogenic range distinct from its natural distribution. This reveals a unique cultural identity developed by ancient transport of this species -- one that continues into the present day."

Cynthia Wilson adds: "The mobility of Indigenous foodways was driven by kinship-based practices across the landscape. Indigenous knowledge holders, especially matrilineal women, held on to these seedlings and stories across generations to sustain ties to ancestral land and foodways."

Funding: This work was funded by the National Science Foundation (Award BCS-1827414). General funding was also received from Red Butte Garden and the Natural History Museum of Utah.