Potato Power: How Andean Farmers Evolved to Digest Starch

A Genetic Link to Diet

A new study reveals that Indigenous Quechua people in the Peruvian Andes have an unusually high number of copies of the AMY1 gene—the gene responsible for breaking down starch.

Published in Nature Communications, the research analyzed the genomes of 3,723 individuals from 85 populations worldwide. The findings show that Quechua people have a median of 10 copies of the AMY1 gene, compared to a global median of 7 copies.

The AMY1 gene encodes salivary amylase, an enzyme that begins digesting starch the moment food enters the mouth. More copies of the gene mean more enzyme production, and a greater ability to process starchy foods.

A Timeline of Adaptation

Genetic dating suggests the increase in AMY1 copy numbers began around 10,000 years ago. This timing aligns precisely with the domestication of potatoes in the Andes, estimated to have occurred between 10,000 and 6,000 years ago.

Researchers attribute this adaptation to natural selection: over generations, individuals with lower copy numbers were less fit, while those with more copies thrived on a starch-rich diet.

"Cases of diet-related genetic adaptation with strong evidence are rare," said evolutionary anthropologist Omer Gokcumen of the University at Buffalo.

Why the Andes?

The Andes provide a unique laboratory for studying human adaptation. Anthropologist Abigail Bigham (UCLA) noted that the region is ideal for examining how selective pressures like diet shape human genetics.

Importantly, other populations without a long history of potato farming—such as those descended from the Maya—do not show the same genetic adaptation.

Evolutionary geneticist Luane Landau (University at Buffalo) emphasized that this comparison supports a direct link between high AMY1 copy numbers and potato consumption.

Broader Implications

The research demonstrates that genetic adaptation to dietary changes can occur on a relatively short timescale—within just a few thousand years.

"The study raises questions about modern diets with globally sourced foods," said evolutionary geneticist Kendra Scheer (University at Buffalo).

This finding highlights how quickly human populations can evolve in response to new food sources, and raises questions about how our ancient genetic adaptations interact with today's diverse, globalized diets.