Long before crops were planted in fields, people in the American Southwest were already transporting useful plants across the landscape.
Now, recent research is revealing that a wild potato was carried across the region more than 10,000 years ago, helping it spread far beyond its natural range.
The study, published in PLOS One, provides evidence that ancient people deliberately carried Solanum jamesii, also known as the Four Corners potato, across the Southwest region of America. The findings indicate that ancient people were transporting plants across large portions of North America well before the development of formal agriculture.
A Potato With a Long History
The Four Corners potato is a small, hardy wild potato that still grows in the southwestern United States and northern Mexico. Today, the Four Corners potato grows in southern Utah and Colorado, as well as in Arizona and New Mexico. Ancient Indigenous communities relied on this plant for food, medicine, and ceremonial purposes, but much of its ancient history was unknown until now.
Researchers examined ground-stone tools from 14 archaeological sites across the Southwest to determine how people used the plant in the past. These sites cover a wide span of time, from recent occupations to deposits over 10,000 years old.
The team used microscopic analysis to identify starch granules on the tools, which form when people process plants for food.
Stone Tools Tell a Deeper Story
Analysis of the tools revealed starch from the Four Corners potato at nine of the sites. Some of the oldest evidence dates back about 10,900 years. Many of these sites are located across the northern edge of the plant’s range in southern Utah and Colorado.
This pattern suggests the potato originally grew farther south and reached the northern portion of the Southwest when Indigenous people brought it there thousands of years ago.
Earlier genetic studies provided additional evidence. Current populations of the Four Corners potato in the northern Southwest show strong genetic links to those found in southern populations. This combination of archaeological and genetic evidence suggests that ancient Indigenous people traveled with the plant across long distances thousands of years ago.
Led by Lisbeth Louderback of the University of Utah, the research suggests that people repeatedly carried and used the Four Corners potato, helping push its range north into areas where it still grows today.
Researchers point out that two behaviors, the repeated use of a plant and its movement beyond its natural habitat, are key signs of early domestication. Although the Four Corners potato never became fully domesticated, the study suggests that people managed its distribution thousands of years before traditional farming began.
Indigenous Traditions
The research team also worked with living Indigenous knowledge holders to better understand the cultural significance of this crop. Through interviews with 15 Navajo elders, the researchers confirmed that people continue to gather and use the Four Corners potato for food and spiritual purposes.
“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,” Louderback said. “This reveals a unique cultural identity developed by ancient transport of this species—one that continues into the present day.”
Co-author Cynthia Wilson added that Indigenous food traditions were determined by social connections as much as by the need to survive. Family-based practices, usually led by women, helped keep both plants and the knowledge about them alive from generation to generation.
Reframing Life Before Farming
This new information about how ancient people used wild plants complicates the usual line drawn between foraging and farming. It also highlights the ways Indigenous communities actively shaped local ecosystems thousands of years before agriculture became common.
The story of the Four Corners potato shows that human influence on the natural world began not with farms, but with people who understood the benefits of these plants well enough to travel with them.
Austin Burgess is a writer and researcher with a background in sales, marketing, and data analytics. He holds a Master of Business Administration, a Bachelor of Science in Business Administration, and a Data Analytics certification. His work combines analytical training with a focus on emerging science, aerospace, and astronomical research.