A new study suggests that natives of Peru may be able to digest potatoes and other starches more easily than the rest of the world.
Scientists have discovered that indigenous Andean people have more copies of genes for saliva-based starch digestion enzymes – called amylases – than any other population worldwide. natural selection Amylase genes increased after the local domestication of potatoes about 10,000 years ago, according to the study published May 5 in the journal Nature. nature communication.
Amylase in human saliva breaks down complex starches into simpler sugars, making the starch easier to digest. worldwide population The number of gene copies varies It encodes for amylase, but more copies means more amylase production and, possibly, improved starch digestion.
On average, people around the world have seven copies of the amylase gene, but indigenous Andean people in Peru have an average of 10 copies. People with a greater number of amylase genes were 1.24% more likely to survive and reproduce than those with fewer copies, the researchers wrote in the study.
Although this number seems small, it is an “extremely high” adaptive advantage that will increase with each next generation, the study’s co-authors Omar Gokkumena professor of biological sciences at the University at Buffalo told Live Science.
Gokkumen said that being able to effectively digest amylase is much more than releasing gas when eating potatoes. The strong survival and reproductive advantage suggests that either not enough children survived because conception was not successful, or people with more gene copies tend to have more children, he said. “It’s really a life or death situation.”
Variation in starch digestion
About 12,000 years ago, ancient people living in the Andes developed several new adaptations, including the ability to survive. High altitude and digesting new foods.
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Previous analysis of the genomes of Peruvians of indigenous South American ancestry revealed signs of Selection of intestinal starch digestion enzymes. This adaptation was probably the result of domestic potato growing by indigenous Andean populations 10,000 years ago.
Gokkumen and his team identified in 2024 variation in structure Of salivary amylase genes in global populations. But the reason for that difference was not clear.
To find out what’s causing the differences, in the new study, Gokkumen and his team created a map of salivary amylase gene copy numbers using genome data from 3,723 individuals from 85 global populations. They found that the Peruvian Andean and Aquimel O’odham peoples in southern Arizona and northern Mexico had the highest average number of salivary amylase genes among the populations they studied.
Indigenous populations in the Andes domesticated the potato about 6,000 to 10,000 years ago.
(Image credit: Tuul and Bruno Morandi via Getty Images)
The researchers found that, about 10,000 years ago, indigenous Andean individuals with 10 or more copies of the salivary amylase gene were 1.24% more likely to survive and reproduce than those with fewer copies – evidence that natural selection led to increased copy numbers in the indigenous Andeans in their sample.
Akimel O’odham samples also showed high copy numbers, but the researchers could not test looking for signs of natural selection in this population because their sample included too few Akimel O’odham individuals.
The functional benefit of having more salivary amylase copies is unknown. Gokkumen said it might have something to do with the microbiome, metabolism and immune system. For example, people with more copies of the gene may get more calories from a baked potato. He said he and his team are now conducting experiments to clarify these possible relationships.
This is an “exciting and important study” charles leeA human genomics expert at the Jackson Laboratory for Genomic Medicine in Connecticut, who was not involved in the new study, told Live Science in an email.
The higher copy numbers in the Akimel O’odham samples suggest that “different Indigenous American groups may have evolved higher amylase copy numbers in different ways, depending on their diets,” Lee said.
Li said that salivary amylase gene copy number variation is unlikely to be the only example of adaptive variation in gene structure. “This is one of the best examples we currently have of how complex copy number variation can intersect with diet, culture and human development,” He said.
Scheer, K., Landau, L.J.B., Jorgensen, K., Karageorgiou, C., Hsiao, L., Alkan, C., Rivera, A.M.M., Osborn, C., Garcia, O.A., Pearson, L., Kiamu, M., Rivera-Cha, M., Leon-Velarde, F., Lee, F.S., Brutsaert, T., Bigham, A.W., and Gokkumen, O. (2026). Rapid adaptive increase of amylase gene copy number in indigenous Andeans. nature communication17(1). https://doi.org/10.1038/s41467-026-71450-8
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