A potato, a human gene, and a trace reaching back roughly 10,000 years: What researchers have found in people from the Peruvian Andes sounds incredible at first. A millennia-long diet of starchy plants may have left a deep mark on the evolutionary history of the local population. At the center of it all is, of all things, the potato.
A major genetic study of 3,723 people from 85 populations shows that indigenous groups in the Peruvian Andes possess an exceptionally high number of copies of the AMY1 gene. This gene plays an important role in the digestion of starch. The timing is particularly remarkable: this genetic trait may have spread significantly in the Andes approximately 10,000 years ago—roughly the same era that marks the beginning of potato domestication in the Andes.
Did potatoes change the people of the Andes?
Not in the way it initially sounds. Eating a potato does not change a person's DNA. Furthermore, the researchers do not claim that potatoes triggered a genetic mutation at some point. What likely happened is far more complex: humans are genetically different from one another, and some individuals possessed more copies of the AMY1 gene than others. When a starch-rich diet becomes part of daily life over many generations, such differences can become relevant for natural selection.
People with specific genetic prerequisites may have had an advantage under these dietary conditions. Over hundreds and eventually thousands of generations, corresponding gene variants can become more widespread within a population as a result. The scientists have found evidence of exactly such a selection process in the Peruvian Andes.
The incredible 10,000-year connection
Here, an investigation into a digestive enzyme turns into a story about human development. The scientists date the expansion of the corresponding genetic variant in the Andes to approximately 10,000 years ago. According to current research, the domestication of the potato also began in the Andes approximately 6,000 to 10,000 years ago.
Particularly interesting in this context is the southern Andean region around Lake Titicaca. This highland region is among the significant cultural and settlement areas of the Andes and played an important role long before the later Inca Empire.
This alone does not prove that the potato was responsible for the genetic development. However, the researchers see a remarkable temporal correlation between the development of a starch-rich diet and genetic adaptation. The potato could thus have been part of a biological process that spanned millennia.
Humans turned a wild plant into food – then evolution went to work
The first farmers in the Andes obviously knew nothing about AMY1, gene copies, or natural selection. They had to produce food under difficult conditions. Over generations, wild potatoes were selected, planted, and further cultivated. From wild plants, one of the most important staple foods of the Andes eventually evolved.
In doing so, humans not only changed the potato, but simultaneously changed their own nutritional environment. A continuously available food source with large amounts of starch could have created a new selection pressure. Humans changed their food—and their food subsequently potentially influenced the conditions under which humans continued to evolve.
Peru stands out in a global comparison
The study is not limited to a few people from a single Andean village. The researchers analyzed genetic data from 3,723 people from a total of 85 populations. In this context, indigenous population groups in the Peruvian Andes stood out with particularly high numbers of AMY1 copies.
An examined population group from Lima also reached a median of ten copies. Across all examined populations, by contrast, the median was seven. This is not proof that potatoes alone are responsible for this difference. However, it is a striking genetic signal that the scientists associate with the long-term development of a starch-rich diet.
Why is AMY1 so important in the first place?
The effect begins with the very first bite. AMY1 contains the genetic information for salivary amylase. This enzyme begins breaking down starch while it is still in the mouth. Potatoes, corn, rice, and numerous other foods contain large amounts of starch.
More copies of the corresponding gene can be associated with higher production of salivary amylase. For people whose diet has been particularly starch-heavy over millennia, this could have meant an advantage. It is precisely at this point that Peru becomes especially interesting for the researchers.
There is a second genetic trace
AMY1 may not be alone. Previous studies also found evidence of natural selection in the MGAM gene among people from the Andes. This gene also plays a role in the processing of carbohydrates.
This leads to a further question: did perhaps more than one single gene react to the changed diet? Multiple components of starch digestion could have been exposed to selection pressure over millennia. The scientists are discussing this possibility; however, a comprehensive adaptation of the entire digestive system has not yet been proven.
No, eating potatoes does not suddenly change your genes
In a story like this, one boundary is particularly important. Anyone who eats potatoes every day today will not suddenly acquire additional AMY1 gene copies because of it. Evolution works over many generations. The study describes a process that may have played out over thousands of years.
Furthermore, the result does not automatically mean that people from the Andes today are inherently better at tolerating potatoes, or that a particularly starch-rich diet would be healthier for them. That has not been demonstrated. The actual message is extraordinary enough already: the dietary history of a population can leave traces in its genetic development—and in this case, that trace leads directly to the Peruvian Andes.
A tuber later conquers the whole world
Millennia after its domestication, the potato left South America. Following the Spanish conquest, it reached Europe in the 16th century. Initially, the foreign plant was viewed with skepticism in many places, but it later transformed the diet of entire continents. Today, it is one of the most important food crops on Earth.
French fries, mashed potatoes, chips, gnocchi, or potato salad have long been part of the daily lives of millions of people who rarely think of Peru in the process. Yet it was there that the story began, long before the global spread of the tuber. Thousands of years later, high cultures emerged in the same Andean world, eventually leading to the Inca Empire with its political center in Cusco. The new genetic research now suggests that the influence of early agriculture may reach significantly deeper than the mere history of a food item would suggest.
The potato was changed by humans – and then the humans changed
This is the astonishing core of this research. Humans domesticated plants because they needed food. These plants subsequently changed their diet, the changed diet created new biological conditions, and under these conditions, certain genetic variants could gain an advantage.
Over thousands of years, this process may have left traces that scientists can still identify in the human genome today. One of the most common tubers in our kitchen thus suddenly becomes a witness to human evolutionary history—and its trace leads roughly 10,000 years back to Peru.
Facts and figures
People examined: 3,723
Populations: 85
Gene in focus: AMY1
Lima: Median of 10 gene copies in the examined group
Median across examined populations: 7 gene copies
Andean-specific expansion: roughly 10,000 years ago
Potato domestication: roughly 6,000 to 10,000 years ago
Nature Communications – Scheer, Landau, Gokcumen et al.: Rapid adaptive increase of amylase gene copy number in Indigenous Andeans, 2026.
Nature – Research on the history and domestication of the potato.
Hero image source: Wikimedia Commons / Cathetovar – Types of Potatoes in Peru, CC BY 4.0.
