Study reports digestive adaptations in Andeans

UCLA and the University at Buffalo reported on May 5 that Indigenous Andean populations in Peru carry unusually high copy numbers of AMY1, a salivary amylase gene tied to starch digestion, in what the researchers described as an adaptation shaped by diet and high-altitude life. The findings were published in Nature Communications in a paper titled “Rapid adaptive increase of amylase gene copy number in Indigenous Andeans.” The work was later picked up in a May 24 science roundup on X that listed it alongside studies on virtual reality and right-handedness. The paper gives the roundup item a firmer frame: this was a genetics study about starch digestion, not a broad claim that Andeans evolved an entirely separate digestive system. ### What exactly did the researchers find in Andean populations? Nature Communications said the study found Indigenous Peruvian Andean populations have among the highest-known copy numbers of AMY1, the gene that encodes a saliva enzyme involved in breaking down starch. UCLA said descendants of potato-domesticating Andean populations in Peru now carry the highest known numbers of that gene of any population studied. Abigail Bigham, an associate professor of anthropology at UCLA, said people with a high number of AMY1 copies tend to produce more amylase in saliva and are thought to digest starch more effectively. The study linked that pattern to Indigenous Andean Quechua speakers in Peru whose DNA was compared with genomic databases containing thousands of samples from dozens of modern human populations, UCLA said. (nature.com) ### Why are potatoes central to this story? UCLA said Indigenous people of the Andes were the first to domesticate the potato, making the starch-rich crop a dietary staple long before it spread elsewhere. The researchers said natural selection began favoring Andeans with unusually high AMY1 copy numbers during the period when potatoes were first grown in the Andean highlands, roughly 6,000 to 10,000 years ago. (newsroom.ucla.edu) Omer Gokcumen, a University at Buffalo professor of biological sciences and a co-corresponding author, said the findings clearly demonstrated natural selection in the Andes after potato cultivation began. Nature’s press summary said the timing of the AMY1 expansion coincides with potato domestication in the region and may reflect adaptation to a starch-rich diet. ### What was the most concrete number in the paper? (newsroom.ucla.edu) UCLA said people with roughly 10 copies or more of AMY1 had a 1.24% survival or reproductive advantage per generation. That estimate is the clearest quantitative claim attached to the study and is the figure repeated in the university and EurekAlert releases. The paper also fits into earlier work on AMY1. A 2007 Nature Genetics study found AMY1 copy number was positively correlated with salivary amylase protein levels and that populations with high-starch diets tended to have more copies, providing background for why the Andean result drew attention. (newsroom.ucla.edu) ### Is this about altitude, diet, or both? The UCLA release framed the result as part of a broader Andean adaptation story. Bigham said the high-altitude Andes are already a key setting for studying human evolutionary adaptation to hypoxia, and that the new work shows the region is also useful for studying adaptation to dietary pressures. (newsroom.ucla.edu) That means the “high-altitude digestion” shorthand in social posts needs some care. (nature.com) The verified finding is a gene-copy expansion tied to starch digestion in Andean populations living in the highlands, with the authors connecting it to potato domestication and life in that environment. The paper and the university release do not say altitude alone caused the change. ### Where can readers find the paper itself? Nature Communications listed the paper as “Rapid adaptive increase of amylase gene copy number in Indigenous Andeans,” published in May 2026. (newsroom.ucla.edu) Phys.org’s summary of the UCLA release identified the DOI as 10.1038/s41467-026-71450-8. The May 24 X roundup that resurfaced the work did not include the journal citation or DOI. Readers looking for the original study can find it through Nature Communications under that title and DOI, with Bigham and Gokcumen among the named researchers. (nature.com)