The results of a study co-led by researchers at UCLA and the University at Buffalo, published in Nature Communications in May 2026, provide another straightforward counterexample to the creationist claim that natural processes cannot add genetic material to a genome without the intervention of their particular magic creator. They also show how relatively recent human evolution can be detected, reconstructed and quantified from the DNA of living populations.
What cannot be observed is the intelligently designed caricature of evolution that creationists are conditioned to mistake for the scientific theory: a single dramatic event in which one species suddenly transforms into an unrelated form. There is no plausible biological mechanism for such a transformation, which is why evolutionary biologists have never proposed one. Biological evolution is a change in the frequency of heritable variants within a population over successive generations; larger differences, including those associated with speciation, accumulate through many such changes.
Young-Earth creationists are nevertheless prepared to invoke evolution at an absurdly accelerated rate when their mythology requires it. To squeeze the present diversity of life into the few millennia supposedly available after their genocidal global flood, a small number of vaguely defined ancestral “kinds” would have needed to diversify into hundreds of thousands of beetle species and countless other forms almost overnight. Yet the same creationists baulk at evidence that human populations have undergone much more modest evolutionary changes over thousands of years.
The new research concerns AMY1, the salivary amylase gene. Salivary amylase begins the digestion of starch in the mouth, and people differ considerably in the number of AMY1 copies they carry. An early duplication of the gene occurred in the hominin lineage at least 800,000 years ago, after which repeated duplications, deletions and inversions generated numerous structural variants containing different numbers of copies. These are mutations that change the amount and arrangement of genetic material in the genome — precisely the sort of naturally arising variation that creationists insist cannot occur.
Crucially, cultivating potatoes did not cause the ancestors of Indigenous Andeans to acquire additional AMY1 copies because they needed them. High-copy variants were already present in the population. When potatoes and other starch-rich crops became dietary staples, people carrying more copies probably produced more salivary amylase and obtained a reproductive or survival advantage. Natural selection then increased the frequency of those pre-existing variants — evolution acting as a filter, not as a designer working towards a predetermined goal.
The researchers analysed AMY1 copy numbers in 3,723 people representing 85 populations. Indigenous Peruvian Andeans had among the highest numbers found, with the Quechua participants carrying a median of ten copies, compared with six among the closely related Maya comparison group and seven across the worldwide sample. The genetic evidence indicates that a high-copy haplotype increased in frequency among Andeans from about 2 per cent to approximately 45 per cent after around 10,000 years ago, coinciding with permanent settlement of the high Andes and the domestication of potatoes between about 10,000 and 6,000 years ago.
The association with potatoes is therefore a strongly supported explanation rather than proof that potatoes were the only selective influence. What is beyond reasonable dispute is that mutation created heritable variation and natural selection altered its frequency within a human population. Moreover, the process began several thousand years before the date assigned to “Creation Week” by traditional Young-Earth chronology, when neither the Andes, its inhabitants nor the potatoes they were domesticating should yet have existed.
The team was co-led by Associate Professor Abigail W. Bigham of UCLA and Professor Omer Gokcumen of the University at Buffalo. Bigham’s team collected DNA from Quechua-speaking people in the Peruvian Andes, which the researchers compared with DNA from Maya participants and genomic datasets containing thousands of individuals from populations around the world.
Human Evolution in Particular Environments. Human evolution did not end with the appearance of Homo sapiens. As populations encountered new climates, diets, diseases and ways of life, natural selection continued to alter the frequencies of advantageous genetic variants. An adaptation need not be beneficial in every setting, nor does it represent perfection: it is simply an inherited characteristic that increased reproductive success under particular conditions.UCLA explained the research in an accompanying news release:
- High-altitude hypoxia — Tibetans, Andeans and Ethiopians. At high altitude, low atmospheric oxygen creates severe physiological and reproductive challenges. Tibetans carry a strongly selected, Denisovan-derived haplotype of the EPAS1 gene, together with selected variants in EGLN1. These help to limit excessive haemoglobin production and the dangerously viscous blood it can cause. Andean and Ethiopian highlanders have evolved partly different genetic and physiological responses to the same problem. This is convergent evolution: similar environmental pressures producing similar functions through different evolutionary routes.
- Kuru resistance — the Fore people of Papua New Guinea. Kuru was a fatal prion disease transmitted among the Fore through mortuary practices in which the tissues of deceased relatives were consumed. Researchers found that a variant of the prion-protein gene, PRNP G127V, occurred only among people from the kuru-affected region and was absent from diagnosed kuru patients. Its distribution indicated powerful recent natural selection, while subsequent experiments showed that the variant could confer strong resistance to prion disease. It is one of the clearest examples of natural selection operating during documented human history.
- Adult milk digestion — European, African and Middle Eastern pastoralists. In most humans, production of lactase, the enzyme that digests milk sugar, declines after weaning. Following the development of dairying, however, several different regulatory mutations near the LCT gene enabled lactase production to continue into adulthood. These variants arose and spread independently in European and African pastoral populations, demonstrating both convergent evolution and gene–culture coevolution: a cultural innovation created a new selective environment.
- Resistance to malaria — populations in malaria-endemic regions. People carrying one copy of the sickle-cell variant of the HBB gene have substantial protection against severe Plasmodium falciparum malaria. Consequently, the variant became common in regions where malaria historically killed large numbers of children. However, inheriting two copies causes sickle-cell disease. This is a classic example of balancing selection and of evolution producing a workable compromise rather than an ideal solution. Other malaria-selected adaptations include thalassaemias, G6PD deficiency and the Duffy-null blood-group variant.
- Breath-hold diving — the Bajau of Southeast Asia. The marine-living Bajau traditionally obtain much of their food by prolonged breath-hold diving. A genetic and physiological study found that their spleens were approximately 50 per cent larger than those of neighbouring Saluan people, including among Bajau who did not themselves dive. Because the spleen releases oxygenated red blood cells when it contracts, a larger spleen provides a greater oxygen reserve. The study found evidence of selection involving PDE10A, associated with spleen size, and BDKRB2, which influences the diving response, although the precise causal pathways remain under investigation.
- Traditional Arctic diet — Greenlandic Inuit. Greenlandic Inuit show exceptionally strong selection around the FADS fatty-acid desaturase gene cluster. These variants alter the metabolism of polyunsaturated fatty acids and have been interpreted as adaptations to a traditional diet rich in marine fats, as well as to aspects of the Arctic environment. Some of the selected variants also affect height and body composition, illustrating how selection on one biological pathway can have several consequences.
- Arsenic-rich drinking water — Indigenous Andean populations. Some populations in the Argentine and Chilean Andes have consumed naturally arsenic-contaminated water for thousands of years. Protective variants of AS3MT, a gene involved in arsenic metabolism, occur at unusually high frequencies in these populations. The variants help convert arsenic into forms that can be eliminated more efficiently in urine, and the surrounding genomic region bears the signature of a selective sweep. This is a striking example of adaptation to a naturally occurring environmental poison.
None of these adaptations appeared because people consciously needed them or because the environment instructed their genes to change. Mutation, recombination and interbreeding first produced heritable variation; individuals carrying variants advantageous under local conditions then left, on average, more descendants. In some cases the result was beneficial only within a particular environment, and in others it carried serious costs. That is evolution as biology describes it: unguided, contingent, frequently imperfect and measurable in the genomes of living people.
Indigenous Andeans have a digestive superpower; researchers think it may be linked to potatoes
Key takeaways
- A new study by researchers at UCLA and the University at Buffalo shows that Indigenous Andean populations carry unusually high numbers of a gene involved in starch digestion, an adaptation shaped by natural selection during the transition to high-altitude living and major dietary shifts 6,000–10,000 years ago.
- Those with roughly 10 copies or more of salivary amylase genes, or AMY1, had a 1.24% survival or reproductive advantage per generation, the researchers found.
- The findings highlight how culture, diet and environment interact to shape human genomes, with implications for understanding metabolism, the microbiome and gene–diet interactions relevant to human health.
Indigenous people of the Andes were the first to domesticate the potato, making the starch-rich crop a dietary staple for this high-altitude population long before it spread to the rest of the world. Today, their descendants in Peru carry the highest known numbers of a gene involved in starch digestion of any population in the world.
Now, a study co-led by researchers from UCLA and the University at Buffalo has discovered that natural selection began favoring Indigenous Andeans with an unusually high number of salivary amylase genes, or AMY1, during the period when potatoes were first grown in the Andean highlands, roughly 6,000 to 10,000 years ago.
Their findings are published today in the journal Nature Communications. People with a high number of AMY1 copies tend to produce more of the amylase enzyme in their saliva and are thought to digest starch more effectively, said Abigail Bigham, an associate professor of anthropology at UCLA who studies populations in the Peruvian Andes and the Himalayas of Nepal.
Bigham and her team of evolutionary anthropologists collected DNA from Peruvian Andean Quechua speakers for the study — data that was then compared with genomic databases containing thousands of DNA samples from dozens of modern human populations.
The high-altitude Andes are known for being a rich region for understanding human evolutionary adaptation — for instance, hypoxia, in which tissues do not get enough oxygen. This new research highlights how the Andes are useful for understanding human evolutionary adaptation to other selective environmental pressures like diet.
Associate professor Abigail Bigham, co-corresponding author.
Department of Anthropology
University of California, Los Angeles, CA, USA.
[Abigail Bingham's] previous work with co-author Kelsey Jorgensen, then a post-doctoral scholar with Bigham, provided evidence of selection in the starch digestion pathway of Andean peoples.
Co-corresponding author Omer Gokcumen, a University at Buffalo professor of biological sciences whose research showed that the initial duplication of AMY1 occurred in humans at least 800,000 years ago, said the findings clearly demonstrated the role of natural selection in the Andes after potato cultivation began.
Biologists have long suspected that different groups of humans have evolved genetic adaptations in response to their diets, but there are very few cases where the evidence is this strong.
Omer Gokcumen, co-corresponding author.
Department of Biological Sciences
University at Buffalo, Buffalo, NY, USA.
Evolution is a sculptor, not a builder
Ancestors of Indigenous Andeans, the researchers said, already carried copies of AMY1 — some with fewer copies, some with more — before they settled into the highlands and domesticated potatoes. When they began growing potatoes, however, those with higher copy numbers gained an evolutionary advantage.
Starting about 10,000 years ago, those with roughly 10 copies or more had a 1.24% survival or reproductive advantage per generation, the researchers found.
Evolution is chiseling a sculpture, not constructing a building. It’s not as if Indigenous Andeans gained additional AMY1 copies once they started eating potatoes. Instead, those with lower copy numbers were eliminated from the population over time, perhaps because they had fewer offspring, and the ones with the higher copy numbers remained.
Omer Gokcumen.
The result? Indigenous people living in Peru today carry an average of 10 AMY1 copies, approximately two to four copies more than any of the 83 populations examined in the study.
Indigenous history in the genome: Did contact with Europeans play a role?
Indigenous people in Peru were found, on average, to carry more copies of AMY1 — 10 versus 6 — than the Maya, an Indigenous population in Mexico with a shared evolutionary history but without a tradition of potato farming.
While the researchers suspected that Andeans’ higher number of AMY1 copies was related to their history of potato cultivation, they still had to account for the dramatic decline in the Indigenous population of the Americas following contact with Europeans in the 15th century, which resulted in disease, famine, violence, conflict and a rapid loss of genetic diversity in a short period of time.
Was it possible that this population bottleneck — rather than natural selection — could have disproportionately removed individuals with lower AMY1 copy numbers? Disentangling the two factors was a major challenge.
In the end, the use of state-of-the-art ultra-long DNA sequencing technologies, along with newly available comparative datasets, allowed the researchers to demonstrate that high numbers of copies of the gene rose in frequency in the Andes several thousand years before Europeans appeared on the scene.
What does it mean now that we all eat French fries?
The study, Bigham said, opens the door to wider research into the lives of people who live at high altitudes and whose daily realities include access to limited foodstuffs and extreme exposure to cold temperatures and ultraviolet rays.
It also raises questions about how humans will evolve from modern food offerings, particularly as access to both diets and global cuisine has, for many, become commonplace. Genetic adaptation, Bigham said, continues to be a factor.
There are ideas out there like the paleo diet, which is adapted to the Paleolithic environment and says we’re not suited to eat foods that come post-domestication. But I think this research shows that human populations have responded and evolved to changing food conditions within the last 10,000 years. Our metabolic pathways are not simply a product of that Paleolithic past.
Associate professor Abigail Bigham.
Other collaborators on the research included researchers from the University of Kansas, Pennsylvania State University, the University of Pennsylvania, the University of Puerto Rico at Cayey, Syracuse University, Cayetano Heredia University in Peru and Bilkent University in Turkey.
Publication:
What the researchers uncovered is a particularly clear example of evolution working exactly as evolutionary theory predicts. Random mutation and recombination had produced people with different numbers of AMY1 copies long before potatoes were cultivated. The adoption of a starch-rich diet then changed the selective environment. Those who carried high-copy variants enjoyed a small reproductive advantage which, accumulated over hundreds of generations, substantially altered the genetic composition of the population.
Gene duplication does not create a completely novel gene from nothing, but it does add heritable genetic material, alter gene dosage and provide additional copies that can subsequently accumulate mutations and acquire new functions. It is therefore one of the principal natural mechanisms by which genomes expand and evolutionary novelty arises. Creationists may try to protect their slogan by redefining “information” so that no naturally occurring genetic change can ever qualify, but that is wordplay, not biology.
Nor can this evidence be dismissed as “only adaptation” or “only microevolution”. Adaptation by natural selection is evolution: the frequency of heritable variants changed over successive generations. Given sufficient time, the accumulation of many such changes produces the larger differences that creationists arbitrarily label “macroevolution”. Humans did not cease to be humans, just as no evolutionary biologist would expect them to; descendants always remain members of the broader groups to which their ancestors belonged.
The chronology is equally unhelpful to anyone trying to force the evidence into a Young-Earth creationist framework. The earliest duplications at the amylase locus occurred at least 800,000 years ago; humans occupied the high Andes thousands of years before the supposed “Creation Week”; potatoes were being domesticated between about 10,000 and 6,000 years ago; and the resulting selective sweep is still recorded in the genomes of their descendants. None of that history could have happened on an Earth created only a few thousand years ago and subsequently scoured by a global flood.
Once again, the scientists found mutation, recombination, inheritance, cultural change and natural selection — all ordinary, measurable processes requiring neither magic nor divine intervention. The potatoes did not deliberately rewrite the Andean genome: they changed the selective landscape, and evolution did the rest.
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