A recent genetic study offers fascinating clues about how the indigenous peoples of the Peruvian Andes managed to adapt and survive in one of the planet's most challenging environments. Researchers from the University of Buffalo analyzed data from over 3,700 people from 85 populations around the world and discovered that Peruvian Andes inhabitants have, on average, the highest number of copies of the gene responsible for salivary amylase.
Amylase is a digestive enzyme present in saliva that helps break down complex starches into simple sugars, facilitating their digestion. This finding largely explains how the ancient inhabitants of the region were able to incorporate potatoes—domesticated in the Andes about 10,000 years ago—as a fundamental part of their diet.
The ability to produce more amylase represented a key evolutionary advantage, according to scientists. Those individuals with more copies of the gene likely had greater reproductive success, while those lacking these additional copies faced difficulties digesting a starch-rich diet.
Omer Gokcumen, one of the study's authors, emphasized the importance of this genetic trait. “It’s really a life or death situation,” he explained. The team focused on Peruvians because the number of samples from another group with high levels, the akimel o’odham of Arizona and Mexico, was insufficient to analyze signals of natural selection.
Millennia of adaptation to the Andean diet
Potatoes, native to the Andes, became an essential food for pre-Hispanic societies. Having more copies of the amylase gene allowed for better nutrition and possibly influenced aspects such as the gut microbiome, metabolism, and even the immune system, although researchers do not yet fully understand all the mechanisms.
The results underscore how environmental factors shaped human biology in Peru, offering a window into the evolutionary history of these populations. The work, published in Nature Communications, opens new avenues for understanding genetic adaptations in different human groups.
