Indigenous Peruvian Andean populations possess the highest known copy number of the salivary amylase gene (AMY1) globally, a genetic adaptation linked to the domestication of potatoes roughly 10,000 years ago. According to research published May 5, 2026, in Nature Communications, this expansion allows for enhanced starch digestion, providing a significant survival and reproductive advantage to those carrying more copies of the gene.
Why do Indigenous Andeans have more amylase genes?
The human body relies on the amylase enzyme, found in saliva and the pancreas, to break down complex starches into simple sugars. While the average person globally carries seven copies of the AMY1 gene, Indigenous Andeans in Peru possess an average of 10 copies. Researchers led by Omer Gokcumen of the University of Buffalo and Abigail Bigham analyzed genetic data from 3,723 individuals across 85 global populations to identify this pattern. Their findings suggest that the rise in gene copy numbers occurred in tandem with the shift from foraging to the cultivation of starch-rich crops like potatoes and quinoa, which began in the Andes between 10,000 and 6,000 years ago.
Approximately 60% of the Peruvian Andean cohort studied by Scheer et al. (2026) carried 10 or more copies of the AMY1 gene.
How does this genetic variation impact survival?
Natural selection favored individuals with higher AMY1 copy numbers because of the tangible dietary benefits provided by increased starch digestion. According to the study, individuals with a higher number of amylase genes had a 1.24% higher chance of surviving and reproducing. While this percentage may appear modest, Omer Gokcumen characterized it as an “insanely high” adaptive advantage that compounded over generations. This evolutionary pressure highlights a “life or death” scenario where the ability to efficiently extract calories from a starch-heavy diet directly influenced reproductive success.
Are other populations showing similar adaptations?
The study identified high AMY1 copy numbers among the Akimel O’odham people in southern Arizona and northern Mexico, suggesting that different Indigenous groups may have independently developed similar genetic traits to manage their specific diets. However, Charles Lee, a human genomics expert at The Jackson Laboratory for Genomic Medicine, noted that the researchers could not definitively test for natural selection in the Akimel O’odham sample due to the limited number of individuals represented. This contrast underscores that while high copy numbers appear in multiple groups, the specific evolutionary drivers can vary based on regional cultural and dietary history.
When examining evolutionary genetics, look for “structural variation”—the way genes are organized and duplicated—rather than just single-nucleotide changes. This is becoming a primary focus for understanding how human populations adapt to diverse environments.
Frequently Asked Questions
- What is the primary function of the AMY1 gene?
The AMY1 gene encodes for salivary amylase, an enzyme that begins the breakdown of starch into simple sugars, making it easier for the body to digest. - Why is the Andean population significant for this study?
The Andes provide a clear timeline for the transition to a starch-rich diet, as the domestication of potatoes in the region roughly 10,000 years ago matches the identified expansion of the AMY1 gene. - Could this adaptation affect the microbiome?
Researchers suggest the functional advantage may extend beyond digestion to the microbiome, metabolism, and immune system, though specific relationships are currently the subject of ongoing experiments.
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