Potatoes may have altered the DNA of the Andean inhabitants

In other words, a diet with lots of potatoes may have been a factor in natural selection.

Details

The researchers studied the AMY1 gene, which is linked to the production of salivary amylase. This is an enzyme that starts breaking down starch already in the mouth. The more copies of AMY1 a person has, the more amylase they can usually produce, and therefore potentially more efficiently digest starchy foods.

The team analysed data from 3,723 people from 85 populations. It turned out that indigenous Peruvian Andean populations had one of the highest AMY1 copy numbers of any group studied. On average, they found about 10 copies of the gene, while the overall median figure for the sample was about 7.

Scientists attribute this peculiarity to the history of the potato. It was the Andean people who first domesticated the potato, and it became an important part of their diet long before it spread around the world.

The authors estimate that natural selection began to enhance the spread of variants with high AMY1 copy number about 6,000 to 10,000 years ago - the same period when potatoes began to be cultivated in the Andean highlands.

Why it matters

The study shows that human evolution did not stop in ancient times. The human genome continued to change well after the advent of agriculture - in response to new foods and ways of eating.

In the case of the Andes, this may be an adaptation to a starch-rich diet. People with more copies of AMY1 probably coped better with such foods and may have had a slight advantage in survival or reproduction.

That said, it's important not to oversimplify the conclusion. The scientists are not saying that the potato "created a new ability" from scratch. Copies of AMY1 already existed in humans, but under the conditions of the potato diet, variants with more copies may have been more likely to persist and be passed on.

Background

AMY1 has long interested geneticists because the copy number of this gene varies widely among people and is linked to dietary history. In populations where there have traditionally been more starchy foods, more copies of amylase genes are usually found. Previous studies have already linked an increase in AMY1 copy number to the transition to farming and a more starch-rich diet.

The new work makes this story more concrete: it shows a localised adaptation in indigenous Andean people and links it to one of the region's most important crops, the potato.

This doesn't mean that modern Andean people are "best at digesting potatoes" in a household sense, nor does it mean that potatoes were the sole cause of selection. But the study shows how a strong nutritional factor could gradually change the frequency of genetic variants in a population.

Source

The study Rapid Adaptive Increase of Amylase Gene Copy Number in Native Andeans is by a team of scientists from UCLA, University at Buffalo and other research centres and published in Nature Communications in 2026; a preprint of the study, which describes the analysis of AMY1 in 3,723 individuals from 85 populations, is also available in open results.