Here is the twist. Potatoes changed you.
Not just your diet. Your DNA.
Ancient Andeans didn’t just farm the tuber. They evolved to eat it. Specifically, to break down the starch hiding inside it. And the proof? It’s sitting in their spit.
A new study, led by teams at UCLA and the University of Buffalo, shows that domesticating the potato acted as a fierce filter on human evolution. We’re talking 6,000 or even 10,000 year ago. That’s when the shift happened. That’s when nature started rewarding people with more copies of a specific gene called AMY1.
Published in Nature Communications, the findings are blunt. Indigenous people in the Andes today hold the record for the highest copy number of this gene in any human group studied.
So, what does AMY1 actually do?
It controls the production of amylase, an enzyme found in saliva. Think of amylase as the first stage of digestion. It attacks starch before food even hits your stomach. More gene copies mean more enzyme. More enzyme means better digestion of starch.
Abigail Bigham, an anthropology associate professor at UCLA, explains it simply. People with higher AMY1 counts process starch more efficiently. Period.
Bigham’s team didn’t just guess. They went to Peru. They collected DNA from Quechua speakers living high in the Andes. Then they pitted that genetic data against a massive global database containing thousands of samples from dozens of different populations.
The contrast was stark.
“The high-altitude Andes have always been useful for studying adaptation,” Bigham says. “Usually we look at how bodies handle low oxygen, known as hypoxia.”
But this time? It’s about diet.
Omer Gokcumen from the University at Buffalo adds context. His earlier work showed humans got their first AMY1 duplication 800,00 years ago. This new data, however, shows a second surge. A rapid spike specifically timed with potato farming in the Andes.
“Biologists have suspected diet changes genetics for a while. But this evidence is unusually strong.”
Nature chisels. It does not build.
Here is how it likely happened.
Long before the first potato sprouted, the ancestors of Andean indigenous groups already varied. Some had a few copies of the AMY1 gene. Some had many. No one changed their DNA by eating potatoes. The DNA was already there, shuffled like cards in a deck.
Potatoes became a staple food around 10,00 years ago Suddenly, carrying many copies became a superpower.
Those with fewer copies struggled to extract energy. They likely had fewer offspring. They faded out. Those with many copies thrived. They survived. They reproduced. The researchers calculated a 1.24% survival or reproductive advantage per generation for people with about ten copies.
Add that up over millennia. The low-copy individuals vanished. Not because they died suddenly. Just because the high-copy carriers filled the demographic space.
“Evolution is chiseling away stone to find a statue. It is not constructing a new building brick by brick,” Gokcumen noted. “The lower copy numbers were eliminated. The high ones remained.”
Today, indigenous Peruvians carry an average of ten copies. Every other population in the study fell two to four copies short. Even the Maya in Mexico, who share deep ancestral ties with Andeans, average only six. The difference? Potatoes.
Was it just a population bottleneck?
One nagging doubt lingered. What about the devastation brought by Europeans in the 16th century? Disease. Violence. Famine. The indigenous population in the Americas collapsed. Could that catastrophe, rather than natural selection over millennia, have accidentally wiped out the people with low AMY1 copies?
The researchers needed to untangle two tragedies: evolutionary pressure over 10,000 verses demographic collapse in the 1500s.
Using ultra-long DNA sequencing, they found a clean answer.
High AMY1 numbers became dominant before the Spanish arrived. Thousands of years before. The potato was the sculptor. Not the conquest.
What does this mean for French fry lovers?
It might break the internet. Specifically the Paleo diet community.
The Paleo argument rests on one simple pillar: humans evolved to eat like hunters and gatherers from 10,00 or more years ago. Anything domesticated since then, so the logic goes, is bad for us. We are stuck in our Paleolithic hardware.
Bigham disagrees.
Her research proves humans adapted metabolically within the last few millennia. We did not stop evolving when farming began.
“Our metabolic pathways are not a fossil from the Paleolithic. We change.”
If potatoes can reshape the genome of an entire mountain-dwelling population, what else has shifted? As food moves across borders, as processed diets dominate, does the story continue?
Bigham leaves it open.
We are still adapting. The question is, are we keeping up with the food on our plates?
Reference: “Rapid adaptive increase of amylose gene copy number in Indigenous Andes” by Scheer et al. Nature Communications (2024). Funded by the NSF, NIH, and the Leakey Foundation.
(Note: Date in original source listed as May 5 2026 – likely a typo in the provided text for a current or 2024 paper. The science stands.) 🥔🧬
