Eating potatoes reshaped the DNA of Indigenous Andeans
Popular Science...
Now a dietary staple around the world, the nutritious potato was first domesticated by the Indigenous peoples of the Andes around 10,000 years ago. It turns out that spuds played such a central role in their diets that their bodies adapted to process the versatile tuber more efficiently. Today, their ancestors have the highest number of genes linked to starch digestion in the world.
Starchy superpower
A study published in the journal Nature Communications, analyzed levels of the AMY1 gene in 3,723 individuals from 85 global populations in genomic databases. AMY1 produces salivary amylase, an enzyme that breaks down starch. Essentially, more AMY1 means more salivary amylase, which means more effective starch digestion.
The team found that Indigenous Andeans have two to four more copies of AMY1 compared to other groups. This starchy superpower appears to have emerged around the same time potatoes were domesticated. That’s when those with more copies of the gene started having a 1.24 percent survival or reproductive advantage per generation. Over time, this meant that natural selection favored those with elevated numbers of the gene.
“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,”study co-author Omer Gokcumen, an evolutionary biologist at the University of Buffalo, said in a statement.
Untangling the root
Indigenous people in Peru, on average, had more copies of the AMY1 gene than the Maya, an Indigenous group in Mexico with a shared evolutionary history but no tradition of potato farming. The researchers had to determine whether this difference was a result of potato cultivation, or if it could be explained by the famine, disease, and conflict that arose after European contact. In other words, they had to make sure what they were seeing couldn’t be explained by who survived colonization.
To untangle these possibilities, the team used computer simulations, advanced DNA sequencing technologies, and several statistical tests. They all confirmed that people in the Andes started seeing the adaptation prior to European contact.
The study raises questions about how modern food offerings may shape humans, said study co-author Abigail Bigham in a statement, especially as access to diets and cuisines from around the world is now common. Our bodies will continue to adapt to what we eat.
“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,” added Bigham. “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.”
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