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Summary: Scientists have uncovered evidence that the domestication of potatoes in the Andes influenced the evolution of human metabolism.
A new study suggests ancient potato farming in the Andes may have shaped human evolution in an unexpected way.
Indigenous communities in the Andes were the first to domesticate the potato, turning this starch-rich crop into a major food source for people living at high altitude long before it spread worldwide. Today, Indigenous descendants in Peru have the highest known copy numbers of a starch digestion gene found in any human population.
A new study led jointly by researchers at UCLA and the University at Buffalo found that natural selection started favoring Indigenous Andeans with unusually many copies of the salivary amylase gene, known as AMY1, around the time potatoes were first cultivated in the Andean highlands, about 6,000 to 10,000 years ago.
Their findings were published in the journal Nature Communications.
People who carry more copies of AMY1 generally make more amylase enzyme in their saliva, which is thought to help them break down starch more efficiently, said Abigail Bigham, an associate professor of anthropology at UCLA who studies communities in the Peruvian Andes and the Himalayas of Nepal.
For the study, Bigham and her team of evolutionary anthropologists collected DNA from Quechua-speaking Andean people in Peru. They then compared those samples with genomic databases containing thousands of DNA samples from dozens of present day human populations.
“The high-altitude Andes are known for being a rich region for understanding human evolutionary adaptation — for instance, hypoxia, in which tissues do not get enough oxygen,” said Bigham, whose previous work with co-author Kelsey Jorgensen, then a post-doctoral scholar with Bigham, provided evidence of selection in the starch digestion pathway of Andean peoples. “This new research highlights how the Andes are useful for understanding human evolutionary adaptation to other selective environmental pressures like diet.”
Co corresponding author Omer Gokcumen, a University at Buffalo professor of biological sciences, previously showed that the first duplication of AMY1 in humans happened at least 800,000 years ago. He said the new findings provide especially clear evidence that natural selection acted in the Andes after people began cultivating potatoes.
“Biologists have long suspected that different groups of humans have evolved genetic adaptations in response to their diets,” he said, “but there are very few cases where the evidence is this strong.”
Evolution is a sculptor, not a builder
According to the researchers, the ancestors of Indigenous Andeans already had different numbers of AMY1 copies before they settled in the highlands and domesticated potatoes. Some carried fewer copies, while others carried more. Once potatoes became a major food source, people with higher AMY1 copy numbers appear to have gained an evolutionary advantage.
Beginning around 10,000 years ago, people with about 10 or more copies had a 1.24% survival or reproductive advantage per generation, the researchers found.
“Evolution is chiseling a sculpture, not constructing a building,” Gokcumen said. “It’s not as if Indigenous Andeans gained additional AMY1 copies once they started eating potatoes. Instead, those with lower copy numbers were eliminated from the population over time, perhaps because they had fewer offspring, and the ones with the higher copy numbers remained.”
Today, Indigenous people in Peru carry an average of 10 AMY1 copies. That is about two to four more copies than any of the 83 populations included in the study.
Indigenous history in the genome: Did contact with Europeans play a role?
On average, Indigenous people in Peru carried more AMY1 copies than the Maya, an Indigenous population in Mexico that shares part of their evolutionary history but does not have a tradition of potato farming. The comparison was 10 copies versus 6.
The researchers suspected that the larger number of AMY1 copies among Andeans was tied to the long history of potato farming. However, they also had to consider the severe population decline among Indigenous peoples in the Americas after European contact in the 15th century, when disease, famine, violence, conflict and rapid genetic loss affected communities across the continent.
One question was whether that population bottleneck, rather than natural selection, might have removed people with lower AMY1 copy numbers at unusually high rates. Separating those possibilities was one of the study’s major challenges.
Using advanced ultra-long DNA sequencing technologies and newly available comparison datasets, the researchers showed that high AMY1 copy numbers became more common in the Andes thousands of years before Europeans arrived.
What does it mean now that we all eat French fries?
Bigham said the study creates new opportunities to investigate the lives of people in high altitude environments, where communities have had to adapt to limited food sources, intense cold, and high ultraviolet exposure.
The findings also raise broader questions about how humans may continue to evolve in response to modern diets, especially as many people now have access to a wide variety of foods from around the world. Bigham said genetic adaptation is still part of the story.
“There are ideas out there like the paleo diet, which is adapted to the Paleolithic environment and says we’re not suited to eat foods that come post-domestication,” she said. “But I think this research shows that human populations have responded and evolved to changing food conditions within the last 10,000 years. Our metabolic pathways are not simply a product of that Paleolithic past.”
Reference: “Rapid adaptive increase of amylase gene copy number in Indigenous Andeans” by Kendra Scheer, Luane J. B. Landau, Kelsey Jorgensen, Charikleia Karageorgiou, Lindsey Siao, Can Alkan, Angelis M. Morales Rivera, Christopher Osborne, Obed A. Garcia, Laurel Pearson, Melisa Kiyamu, María Rivera-Ch, Fabiola León-Velarde, Frank S. Lee, Tom Brutsaert, Abigail W. Bigham and Omer Gokcumen, 5 May 2026, Nature Communications.
DOI: 10.1038/s41467-026-71450-8
The work was supported by the National Science Foundation, National Institutes of Health and the Leakey Foundation.
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